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How to Calculate Standard Deviation

Updated on July 20, 2013

How to do standard deviation, listing the 6 simple steps required, showing the process manually and also describing how to do it using Excel - includes links to a downloadable spreadsheet of the examples given.

Six straightforward steps on how to Calculate Standard Deviation ;-

1. Get the Mean

2. Get the deviations

3. Square these

4. Add the squares

5. Divide by total numbers less one

6. Square root of result is Standard Deviation

--------------------------------------------
SO STEP BY STEP;-

1. get the Mean

to begin you need the mean or the average, for example add 23, 92, 46, 55, 63, 94, 77, 38, 84, 26 ... = 598 divide by 10 (the actual number of numbers) 598 divided by 10 = 59.8

so the mean or average of 23, 92, 46, 55, 63, 94, 77, 38, 84, 26 is

59.8

____________________________________________________

2. get the deviations

subtract the mean from each of the numbers, the answers are;-

-36.8, 32.2, -13.8, -4.8, 3.2, 34.2, 17.2, -21.8, 24.2, -33.8

____________________________________________________

3. square these

to square means multiply them by themselves, the answers are;-

1354.24, 1036.84, 190.44, 23.04, 10.24, 1169.64, 295.84, 475.24, 585.64, 1142.44

____________________________________________________

4. add the squares

total of these numbers is 6,283.60

____________________________________________________

5. divide by total number of numbers less one;-

you had 10 numbers less 1 is 9 numbers

so 6283.60 divided by 9 = 698.18

_____________________________________________________

6. square root of result is Standard Deviation

square root is the number multiplied by itself to get 698.18 which is:-

26.4 so 26.4 is the Standard Deviation...

_____________________________________________________

Ok so above is the manual method of doing this

_________________________________________________

Step by step example using Excel...


Calculating standard deviation using Excel

.


Step 1

Enter your range of numbers as shown in cells 1 to 10..

Step 1 - Photo 1

Step 2

place the cursor in Cell 11

go to the menu bar, select insert, select function - the insert function dialog box opens.

Click on the category and select Statistical

In the window below select Average

hit enter

Step 2 - Photo 2

Select the Insert Function
Select the Insert Function

Step 2a

When you hit enter another dialog box will appear asking you to confirm the range, i.e. the numbers in cells 1 to 10 that you wish to perform the calculation on.

Just hit enter

The Mean or Average will now appear in Cell 11

Step 2a - Photo 2a

Step 3

Place the cursor in Cell 12

same as before Go to the menu bar, select insert, select function

The function dialog box will open, select statistical, in the window below scroll down and select STDEV

Step 3 - Photo 3

Step 4

When you hit enter another dialog box will appear asking you to confirm the range, i.e. the numbers in cells 1 to 10 that you wish to perform the calculation on. Since it automatically seeks to perfrom the calc on all the cells above you will have to change the range from D4:D14 to D4:D13

The Standard Deviation will now appear in Cell 12

Step 4 - Photo 4

Pat yourself on the back if...

your final calc matches this...

and the Final Score is...26.4

What Does Standard Deviation Tell You

Standard deviation is all about dispersion - how the set of numbers or data you have deviate from the Mean, this is essentially a measure of uncertainty.

  • Low Deviation shows the numbers are all reasonably similar
  • High Deviation shows there is a lot of fluctuation in the numbers.

How can you use it;-

  • Conducting investment research since this is an aid to measuring or calculating volatility.
  • Making weather comparison between locations or year to year
  • Analysing agricultural yields and/or prices
  • Almost everything to do with population analysis
  • Lots of things in sports, with athletes, teams performances, motorsport, horse racing

All these analyses help in prediction by looking closely at past performance.


Example - Using Deviation to analyse hub scores

Just say we were using Deviation to analyse hub scores, in the example below all the hub scores are above 90, when the SD is calculated for this range the SD is 2.92. this is low, as a contrast the original calc has hub scores from 23 to 94 in other words there is a lot of volatility...

So if one wished to rank hubpages it may be that those with a lower Standard Deviation i.e. less volatility are more consistent... and so we enter the esoteric world of statistics... imagine this was horses....

An Example of Using SD

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    • profile image

      IĆ°unn 10 years ago

      nicely done~

    • Drax profile image
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      des donnelly 10 years ago from NYC....

      thanks Iðunn

    • profile image

      chopiex_bilaz' 9 years ago

      After i read your the page, i'm able to finish my statistic project..thankx dude

    • Drax profile image
      Author

      des donnelly 9 years ago from NYC....

      hey chopiex_bilaz', no problem.. the power of the Net, isn't it great... cut copy and paste that homework...

    • Mystic Biscuit profile image

      Mystic Biscuit 9 years ago from Phoenix, AZ

      Love it, Drax.....the SD calculations, the Excel and the especially the poetry!! ;-)

    • Drax profile image
      Author

      des donnelly 9 years ago from NYC....

      Hey Mystic Biscuit, great name... thanks very much, I should do more of this Excel stuff some of these days since it is almost a form of relaxation...

      ..Drax..

    • profile image

      kk 9 years ago

      awesome man!

    • Drax profile image
      Author

      des donnelly 9 years ago from NYC....

      thanks KK, I really really must do more of these....

    • mndheather profile image

      mndheather 9 years ago from India

      very very informative, illustrated in a very simple way.

      http://www.jasfy.com

    • Drax profile image
      Author

      des donnelly 9 years ago from NYC....

      Hey Mndheather - thanks for the comment, Drax...

    • CarpetDiem profile image

      CarpetDiem 9 years ago from Southern California

      hi Drax, you should write a hub on how to get a hub score of 100. Wow!

      I cheat and use my calculator to get a standard deviation. One thing I think that you could add to this hub (if you wanted to, but it is already a 100) is a bell curve graph to show the significance of standard deviation. If I remember correctly from school (a long time ago), x% of the data will fall within plus or minus 1 std dev, y% plus or minus 2 std dev, and I think its 99.7% will be within plus or minus three std dev. If you have enough data to calculate an accurate std dev, you can then determine the likely values of any new incoming data - would be good for a hub on how to make a living in Las Vegas...

      Now about how you get that score of 100....

    • Drax profile image
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      des donnelly 9 years ago from NYC....

      CD thank you for the great suggestion, I must revise this again... with regard to the 100 I think it relates mostly to incoming hits from google searches, when they are high the score is high so there is a correlation of sorts there....

      Thanks Drax...

    • CarpetDiem profile image

      CarpetDiem 9 years ago from Southern California

      Drax, I see that this hub is now a 91. Interesting that the hub score fluxuates based on the number of incoming hits. I wonder what the standard deviation of the fluxuation on this hub is... :)

    • Drax profile image
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      des donnelly 9 years ago from NYC....

      CD and today (Mon May 19th) it is 93.. maybe some of these days I'll sit down and plot this...

      thanks Drax..

    • profile image

      Sarah 9 years ago

      A word of advise, as a University academic, do not use wikipedia to get your answers as most of the time the information is just presented from people, and not from trustworthy sources.

    • Drax profile image
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      des donnelly 9 years ago from NYC....

      thanks Sarah... hmmm... as a university academic it might be good to know the distinction between advise and advice.. I like wikipedia, especially because it is not perfect or does not pretend to be. This is much better than say Govt pretending that everything they say is truth....

    • profile image

      abhinav 9 years ago

      thnx a lot for such a small and easy way of understanding the standard deviation.

    • Drax profile image
      Author

      des donnelly 9 years ago from NYC....

      Abhinav I'm glad it was useful to you.... tell others... thnaks Drax

    • profile image

      Tori 8 years ago

      Wow, exactlly what i needed help in THANK YOU i just got an A+ on my HW =D... your example is the simpliest out there on the web, and easyest 2 understand, thanks again!

    • Drax profile image
      Author

      des donnelly 8 years ago from NYC....

      Hey Tori, nice of you to say so, thanks very much... Ciao Drax

    • profile image

      CEM 8 years ago

      Hey there,

      THANKS for this!!! Loved the pic editorial, it was very helpful and easy to understand. I finally got it (at least I hope so) after many frustrating tries.

    • Drax profile image
      Author

      des donnelly 8 years ago from NYC....

      all right Cem, good that this continues to be useful... thanks for the comment..

    • profile image

      Polong 8 years ago

      Thank you so much...

    • profile image

      Polong 8 years ago

      how to calculate the IRR?

    • profile image

      Rowan 8 years ago

      cudn't ask for a better explanation. Thanks a million. Got an awful teacher who confused the entire topic (like everything else he teaches.) Got an exam tomorrow and jst conceptualised it. You may have just saved me from failing the exam. Thank you sincerely. Loved the poems as well.

    • Drax profile image
      Author

      des donnelly 8 years ago from NYC....

      Hey Rowan, thanks, glad it was of use to you, I hate that when teachers cannot get the knowledge across...

    • profile image

      Es 8 years ago

      Can you tell me why it's( Deviation) devided by n-1 but not by just n. What does it really mean?

    • Drax profile image
      Author

      des donnelly 8 years ago from NYC....

      Hey ES to be perfectly honest I have no idea but I will go and look it up just as soon as I have time and I'll post the answers here within a few weeks..

      Thanks Drax

    • profile image

      Grateful Alive 8 years ago

      Thank you for sharing the steps to calculate the standard deviation. You rock!

    • Drax profile image
      Author

      des donnelly 8 years ago from NYC....

      hey great user name, thanks for the thanks regards drax

    • profile image

      Matt 8 years ago

      Thanks heaps for this example! It's by far the easiest to understand. I now understand Standard Deviations! lol.

    • Drax profile image
      Author

      des donnelly 8 years ago from NYC....

      Hi Matt,

      thank you very much for the comment, it is always nice to get encouragement.

      Regards

      Drax

       

       

    • profile image

      Noor 7 years ago

      Chrisssssssssssssss U'r Owsaaaam, U really help me xxxxxx

    • profile image

      Dots... 7 years ago

      Thanks. Really helps in schoolwork.

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Hey Dots... use the technology... cut that homework time in half... :-)

    • profile image

      seb 7 years ago

      cheers drax you're my hero.

    • Sexy jonty profile image

      Sexy jonty 7 years ago from India

      Very well written hub .....

      very much informative ......

      Thank you very much for your great hub, for good advice, good wishes and support. Thanks for sharing your experience with all of us.

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Hey thanks very much Seb

      Regards Drax..

    • Drax profile image
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      des donnelly 7 years ago from NYC....

      Hey thanks Sexy... ;-) Regards Drax..

    • profile image

      clever man 7 years ago

      hi Drax..... i read a lot of sites about(Calculate Standard Deviation) but i cuod not understand...

      now after i read your page understand 100%

      great explanation

      Excel explanation very great

      its all Really helps

      thanks a lot

      ( pls forgave me for my bad inglish)

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      thanks man, nice to get a compliment from a Clever Man :-)

      great name..

      Cheers

      Drax

    • profile image

      clever man 7 years ago

      hi Drax..... thanks for your reply

      i wonder if you can help me in the following :

      Linear Regression Indicator ...

      calculation....

      how To do linear regression indicator with excel

      again and again thanks a lot

    • profile image

      Ahmer 7 years ago

      DUDE THE SQUARE ROOT IS NOT THE NUMBER MULTIPLIED BY ITS SELF

    • profile image

      eric 7 years ago

      this is great, thanx for making it easy

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      no problem Eric, it's great that this hub has proved to be helpful to everybody...

    • profile image

      Areif 7 years ago

      Its really cool way of explaining! This is simple this is useful, you made complex definition to simple and understandable. Good Job.

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Hey Areif... thanks for the comment and delighted it was of some use to you...

    • profile image

      no point 7 years ago

      It doesn't answer the question how to _calculate_. It just tels what the deviation is.

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Well No Point... if you read it and follow the 6 steps telling you how to calculate it then you can apply the same rules to any set of numbers... ? so it tells you how to do it step by step...

      1. Get the Mean

      2. Get the deviations

      3. Square these

      4. Add the squares

      5. Divide by total numbers less one

      6. Square root of result is Standard Deviation

    • profile image

      Cindy  7 years ago

      Excellent example for beginners thumb up**

    • profile image

      adriana  7 years ago

      thank you so much! explained so much better then my book and professor!

    • profile image

      yumna  7 years ago

      thanxxxx 4 such a nice help

    • profile image

      13 7 years ago

      Thanx

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Thanks for the comments folks :-)

    • profile image

      frooty 7 years ago

      can anybody tel me the procedure to calculate standard deviation by a calculator...???

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Hi Frooty, if you follow the steps 1 to 6 above using the calculator you will get the result...

    • adorababy profile image

      adorababy 7 years ago from Syracuse, NY

      I can't believe I am looking at the standard deviation formula again. It has been ages but thank you for the reminder though.

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Thanks Adorababy... I know when you get away from it you never want to go back unless someone is paying you :-)

    • ss sneh profile image

      ss sneh 7 years ago from the Incredible India!

      Hi! Back to school grade 6! Thanks for helping us go back in time! -- Thanks

    • Drax profile image
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      des donnelly 7 years ago from NYC....

      Hi ss sneh... glad it was useful :-) ..Drax

    • profile image

      kp 7 years ago

      its really a gr8 work.. easy to understand..

    • Drax profile image
      Author

      des donnelly 7 years ago from NYC....

      Hey KP... glad it was of some help... that is all each of us needs.. just a little help :-)

    • profile image

      Jha 6 years ago

      Nice post!! Great work!!

    • Drax profile image
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      des donnelly 6 years ago from NYC....

      Hey Jha thanks :-)

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      Tony.P 6 years ago

      Great info - Many Thanks for this site

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hi Tony.P... glad you liked it and thanks for the comment :-)

    • profile image

      Lina 6 years ago

      omygosh! thanks so much! Deadline for my stats assignment is tmr and this practically save my life!! huge amount of thanks (: (: (:

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hey Lina... that's great :-) glad it was of some help.. Thanks Drax

    • profile image

      beauty 6 years ago

      thanks so so much, u really helpd me & now i understand

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hey Beauty... good it was useful... :-)

    • profile image

      domingo f. samonte 6 years ago

      the topic is very informational and easy to understand. i believe it will be more useful for a beginner like me if you have time to illustrate also by example how to draw a bell curve for the given example data.thank you very much

    • Drax profile image
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      des donnelly 6 years ago from NYC....

      @submitedgeclb thanks for the very nice comment... keep up the studies... !!!

    • Drax profile image
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      des donnelly 6 years ago from NYC....

      @Domingo... thanks for the comment, I will definitely come back after Xmas and make more hubs around this theme...

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      Manjusha 6 years ago

      good explaination

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      thanks Manjusha :-)

    • profile image

      Shivaprakash 6 years ago

      Thanks a ton i really learnt more from this dude thank u very very much

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hi Shivaprakash... that's great.. I really really must do more of these... :-)

    • profile image

      savvy 6 years ago

      On an employee survey using an interval scale where 1 is low and 5 is high, which of the following results would show a distribution of responses with the most number of employees responding favorably, based on a response of 500 employees?

      a) Mean = 4.0; standard deviation = .30

      b) Mean = 4.2; standard deviation = .99

      c) Mean = 4.5, standard deviation = .89

      d) Mean = 3.9, standard deviation = .75

      the answer is a.

      How would you explain this?

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hey Savvy although I am tempted to look at this in detail time does permit me to do so at this juncture... sorry mate...

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      Besure 6 years ago

      this is simply great! :-) thnx lot Drax!

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hey Besure... thank you for the comment, I'm glad to hear it... :-)

    • profile image

      SUPAMAN 6 years ago

      Thanks men... very very simply and clear. Any easier and my brain would have melted lol... Thanks. Lab report, DONE!

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hey Supaman... thanks for the comment.. :-)

    • profile image

      Janna 6 years ago

      Thanks so much Drax! You really made it simple, I finally understand standard deviation!

    • profile image

      vsk 6 years ago

      thank uuuuuuuuuu

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      @ Janna... that's great that is was useful to you... happy days :-)

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      @VSK... no probs... my pleasure :-)

    • profile image

      kully 6 years ago

      this helped alot! thanks

      i was wondering if you could tell me how to work plus 1 S.D and minus 1 S.D

      is it basically adding and subtracting the means from each number in the data??

      your help is greatly appreciated

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      Hey kully... if you could expand the question a little it would be a big help in trying to answering it...

    • profile image

      municipal vehicle hire 6 years ago

      Such a very interesting information. We are currently studying how to get standard deviation, and it's somehow challenging due to different solving strategies.

    • Drax profile image
      Author

      des donnelly 6 years ago from NYC....

      MVH... that is very encouraging... to be able to solve a mathematical issue... what else is there in life... :-)

    • profile image

      plumbing 6 years ago

      Thanks for this. Very interesting. Nice post!

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Plumbing... your url goes to an external source... this is not really cricket... I have resisted the temptation to delete you, this once... join us here at Hubpages share the knowledge and experience...

    • skyfire profile image

      skyfire 5 years ago

      I use both excel and opencal (open office) and found that this is one good method for the deviation. Thanks for posting these pics, they were helpful.

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Hi Skyfire... (great name !!!) thanks for the comment...

    • profile image

      Dani 5 years ago

      Thank you! This helped me organize my chemistry work!

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      that's good Dani... use the webtech, always... :-)

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      Tony 5 years ago

      How do i find the standard deviation using likert scale

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Hi Tony... just convert your responses to numbers... if you had the standard Likert - the format of a typical five-level Likert is:

      Strongly disagree

      Disagree

      Neither agree nor disagree

      Agree

      Strongly agree

      number this 1-5

      1. Strongly disagree

      2. Disagree

      3. Neither agree nor disagree

      4. Agree

      5. Strongly agree

      so say 16 people responded;-

      q1 3

      q2 2

      q3 4

      q4 6

      q5 1

      so your series is 3by1,2by2,4by3,6by4 1by5

      the data set is then 3 of 1, 2 of 2, 4 of 3, 6,of 4, 1 of 5

      so multiplied out 3,4,12,24,5

      or you could do it listing them all...

      1,1,1,2,2,3,3,3,3,4,4,4,4,4,4,5

      so then just take these and proceed from Step 1 and go through the whole deviation process above...

      :-)

    • profile image

      mrs.millis 5 years ago

      this didn't work why is it on the internet?

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      @mrs millis... what did not work,? if you would care to tell me more precisely then I could help you out with whatever part you are not doing right... :-)

    • profile image

      Missunderstood 5 years ago

      hey Drax,

      After reading the posts made, it seems like u never answer back questions. Instead u just thank people for their compliment...

      -I am Miss-understood about this

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Well Missunderstood, G'Day to all in Perth.. in order for me to understand what is the question or problem being faced by a reader I often need to ask for clarity, or for clarification, in order to be clear that I am not simply being misunderstood, if you understand...

      Yet, understandably the people who often misunderstand or do not return with clarification of their question or tell me what they do not understand are not members of the Hubpages community, they are passers by, they offer nothing, they do not contribute, they are the hyenas/dingos of online society, just flotsam in the great rush of the humanity all carried forward towards electronic understanding...

      I assume you have empathy with them and so can understand Misunderstood...

      Ciao

      Drax

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      Tommy 5 years ago

      thanks a lot!

    • profile image

      matt 5 years ago

      very helpful thankx

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      @Tommy & Matt... thanks very much for the comments, it is always very rewarding when anyone comments.. :-)

    • profile image

      sandy 5 years ago

      thanks a lot author....your explanation is very easy to understand....it is very much useful to me...

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Hey Sandy... great to hear that, my name is Drax... from Ireland :-)

    • profile image

      Baffa 5 years ago

      nice work. i understand it here more than what i have been thought

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Hey Baffa... that is good I am glad, this is always what I find wrong with school stuff, just explain it to me mf... it is your job ;-)

    • profile image

      fateme 5 years ago

      Hi

      thank for your help

      our proffesor teach our standard deviation and variance and error bar.

      i neeed to know how i can using excel to plot the diagram

      my data just 50 numbers

      please help me

      thanks a lot

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Fateme

      here is the above as a google doc, just download it as an excel sheet :-)

      https://docs.google.com/spreadsheet/ccc?key=0ApwEP...

      if you need more than this then tell me exactly what you need and I will do my best to answer or give you a working example

    • profile image

      WhiteSnow 5 years ago

      Hi Drax,

      Thank you so so much, u really helpd me & now i understand what is it Standard Deviation

      COuld you help me forvanother question, please?

      I don't understand what my instructor want for this homework

      He would like me to 2. Use the Excel Descriptive Statistics tool (from the Analysis ToolPak) found in: File > Options > Add-Ins > Analysis ToolPak > Go > Analysis ToolPak (select) > OK. Then the Data Analysis tool will appear on the right of the Data ribbon.

      And then question is

      a. Obtain the descriptive statistics for Question #3: How many hours per day do you spend in total on Facebook, phone texting and e-mail? Format all non-integer values to two decimal places.

      b. Are the data skewed? If so, in which direction and by how much?

      He gave us a data but I don't know what he means and what I need to do

      Could you help me,please?

      Thank you very much

    • profile image

      katie 5 years ago

      Thankyou it was good made me pass my homework mock exam as i copied and pasted it all :D x

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      @ WhiteSnow... Hi thanks for the great comment, I will make a quick hub about using the Excel Descriptive Statistics tool

      https://hubpages.com/education/How-to-Use-the-Exce...

      :-)

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Hey katie... that's great... use the tech but try and understand it as well... :-)

    • profile image

      WhiteSnow 5 years ago

      Hi Drax,I for got to telll you that I used Excel 2003 version so I don't know it will make any different because my instructor used Excel 2007.

      That's Analysis ToolPak also related to Creating a TRUE Excel Histogram for another home works.

      I really appreaciate for you trying to help Drax because I would like to understand what I am doing but instructor did not explain

      Thanks

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      WhiteSnow... so check out https://hubpages.com/education/How-to-Use-the-Exce...

      and for histograms they are easy, go to to Tools, Data Analysis, select Histogram.. input your range as you did before and experiment with the settings to answer the specific question you are being asked..

    • profile image

      BakerBoy97 5 years ago

      This is awesome I searched like ten other sites then I found this one. It is definitely the best. Cheers Drax!

    • profile image

      Abby 5 years ago

      This really helped me out for my Algebra 1 honors (: Thanks lots!

    • profile image

      5 years ago

      thanks it really help me with my honors algbra homework

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      @ BakerBoy97 ... that's great... I must try to promote it more... tell somebody :-)

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      @ Abby magnifico !!! I was useless at algebra... I never found a teacher who cared enough to explain it to me properly...

    • profile image

      Sara 5 years ago

      ii know how to do tis in school we do it 100 times a day i have it memerised did i mention i am 12?

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Well Sara... that is fantastic, it is great to have the talent to be able to memorise mathematical things... it's good for the brain .. like running :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Well Sara... that is fantastic, it is great to have the talent to be able to memorise mathematical things... it's good for the brain .. like running :-)

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      Sizz 5 years ago

      really well and clearly explained, thank you so much! brilliant help to me this was!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Sizz... thank you for saying so, it is appreciated :-)

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      Sheshe32 5 years ago

      i absolutely love this after 20 yrs out of school i was unable to have this make sense wow thank you so much!! :)0

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hey thanks Sheshe... I feel that a lot when I cannot understand WTF they are trying to tell me....

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      FruitySnoops 5 years ago

      Thanx a lot!!! very very awesome. keep it up

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hi FruitySnoops... thanks for the comment !!

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      Ronald 5 years ago

      You saved my life dude!

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      PrimaD 5 years ago

      AWESOME!!!!!!!!

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      Swapnil 5 years ago

      Tnx...it was very helpful :)

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      puzzled 5 years ago

      What if you have a missing data, how do you find it if you have a standard deviation of 3?

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Ronald... good man Ronald, thanks... keeping the old life statistics current is a good habit... !!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hey PrimaD... good is awesome is good... thanks a lot :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hi Swapnil... good of you to say so... thanks !!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Pazzled... missing data usually cannot be found, you have to guess... it depends on what % of data is missing, if say 30% of the results are missing or just 1%.

      Depending on the data size here are 4 choices;-

      1. the questions/cases are deleted with the missing data, if it is small percent of overall study, answers, number range

      2. You use Single Imputation which means you use other methods to help you guess the missing values, the real simple way is to use the mean or median

      3. Next you can use complicated things like stochastic regression or EM Imputation to help predict.

      4. Multiple Imputation really means using more complicated tools to predict but now your whole data is becoming more unreliable.

      If you are not missing lots of data you could simply use the mean or the median and then you could make a little table of the deviation using both sets of data to show you know it makes a difference, your table could have SD with these three sets of figures...

      1. with the missing data

      2. just substituting the missing with the mean

      3. just substituting the missing with the median

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      Deen mohammad 5 years ago

      very usefull...easy to understand..thanks

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      pauline 5 years ago

      hi, i am really learning and i am enjoying your piece of work i hope i understand these better. since it is simplified for those who are slow learners!!!!!!!!! thanks a lot.

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      Shiji 5 years ago

      Such a wonderful presentation!!!!!!!!!!!!!!! Thanks dude

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      Lal Nabi 5 years ago

      very good way to learn something. easy way for understanding.

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Deen Mohammad... thanks very much, it is good to know this always !

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Pauline.. thanks for the comment, deviation is a tricky subject and it is always important to learn the fundamental, then you never forgot :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Shiji... thanks very much for the comment, it is appreciated !!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Lal Nabi... I am very glad that it can help convey what deviation is all about, thanks for the comment !!

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      Lal Nabi 5 years ago

      why we use standard deviation means what is the application of standard deviation..

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      IB_MatheMacigian 5 years ago

      Great, simple quidance, but isn't this the formula for the unbiased estimate of the population variance, rather than the standard deviation which only consideres the sample given?

      Difference between these two would be in step 5, for standard deviation one does not need to substract 1 from the divisor. :)

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      lakee 5 years ago

      You made it really simple for me buddy!! Thanks!

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      amit 5 years ago

      hey how to calculate the standard error of xy plot????

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      Ragini Zatale 5 years ago

      Thnks alot .......it was so useful to me...

    • profile image

      shunaynay 5 years ago

      thanks:) helped me alot for my hmwk!!!!

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      Tom 5 years ago

      Thats was fantastic. I think this is all I needed and really helped moi. Thanks man!!

    • profile image

      S ANIL KUMAR 5 years ago

      I think it's better

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hi folks... thanks for much for all the comment, I see a number of questions contained in these last comments and I will definitely try to make additional hubs addressing these aspects... Thanks to All !!

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      Mel 5 years ago

      Awesome example on standard deviation. Very helpful.

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hi Mel... thanks very much for the comment :-)

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      RG 5 years ago

      veryyyy veryyyy veryyy helpful. thanks :)

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      Sara DK 5 years ago

      Thanks a lot :) Very helpful step by step for my research assignment!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @ RG verry verry good lol :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Sara... thanks, glad to be of assistance...

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      Blake 5 years ago

      This is Awesome!!!!!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hey Blake... thanks for the comment :-)

    • louromano profile image

      louromano 5 years ago

      this is great, thanx for making it easy

    • profile image

      lily lombardo 5 years ago

      thanks for all the help. It helped me a TON!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @louromano great that you found it to be of some help... thanks for the comment :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @lily lombardo... thank You.. for the comment :-)

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      priyanka 5 years ago

      thanks u make my efforts easy

      the description is so simple....thank u so much

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @ priyanka.. that is excellent since that was the objective to make it able to be understood... thanks for the comment ... :-)

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      QuntileIndiangirl 5 years ago

      thnks drax i really needed this for hw i did this before but didn't understand now i do.

      thanks

      kimberly

    • profile image

      Marius 5 years ago

      Greatings from Norway:-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hi Kimberly... thanks for taking the time to post a comment and I am glad it was of help.. :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hi Marius.. greetings from Ireland :-)

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      shalini 5 years ago

      Thanks soo much..timely help

    • profile image

      kus kuas 5 years ago

      hi, thanks man, u helped me do my assignment

    • Eileen Goodall profile image

      Eileen Goodall 5 years ago from Buckinghamshire, England

      I remember everyone struggling with this when I did my Psychology stats - great posting!

    • pandula77 profile image

      pandula77 5 years ago from Norway

      Hey Drax, thanks for the info. A complex topic made easy. voted up!

    • profile image

      Shini 5 years ago

      Hi Drax, thanks for giving stepwise information about SD

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @shalini... glad it was right place right time.. :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @kus kuas... thanks for the comment !!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Eileen Goodall.. thanks Eileen, I feel the same about algebra, it is always frustrating if the fundamental is not explained clearly to you in school..

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @pandula.. thanks very much for the vote up !!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Shini.. thanks a lot for taking the time to comment :-)

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      Grace 5 years ago

      This is by far the most helpful and strait forward explanation I have ever seen. THANKS!

    • Robert Erich profile image

      Robert Erich 5 years ago from California

      Very helpful information! Thanks for writing. I Googled help to find this and found a fellow hubber as the top result! Great to know that we can make it up there. Look forward to stumbling upon you again!

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      jacob 5 years ago

      this helped me in my statistics exam

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Grace... thanks for the comment and for the nice words.. :-)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @ Robert Erich... yes it is nice to be at the top of any Google search :-) thanks !!

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      @Jacob... that's good since this is the whole idea, to be able to convey what it is about... thanks for the comment :-)

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      kaila 5 years ago

      this is very helpful for me, except it doesn't work when you divide by the number less one.... you need to divide by the number to get the correct answer

    • profile image

      Kaila 5 years ago

      this is a really hlpful page and its very much appreciated that you take the time to explain how to figure out standard deviation, although i have to say that when you say you divide the total number less one. i find that my answers are never correct. they are only correct when i divide by the total numbers. the equations in my foundation math book also say that it is divide by total numbers. it says nothing about divide less one. other than that this page helps keep me on track until i have it memorized. so thank you

    • Drax profile image
      Author

      des donnelly 5 years ago from NYC....

      Hi Kaila.. thanks for the comment :-) there is a difference in the formula for calculating Standard Deviation if the set of numbers you have is the entire Population or a Sample of the entire Population -

      for the Population it is N

      for the Sample it is N-1

      ..if you would like to post your numbers I will take them and make examples to show what happens with the formula !!

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      tahoor khan 5 years ago

      very well done

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      thank you Tahoor Khan :-)

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      hello from kenya 5 years ago

      fantastic those steps has enabled me to understand how to calculate standard deviation.

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      Hello .. hello from kenya :-) this is excellent and I am delighted to know this helped in some small way... thanks Drax

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      hpgc 5 years ago

      absolutely brilliant!!

      thanks for the hard work

      saved me heaps of time =)

    • Drax profile image
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      des donnelly 5 years ago from NYC....

      HPGC... that's great !! this is exactly what Hubpages is about... people sharing stuff that saves time and adds value in some small way... :-)

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      whowas 5 years ago

      That is one of the clearest expositions of the methods of calculating standard deviation that I have ever seen. really, some tutors do seem to make these things unnecessarily complicated.

      Most mathematical and statistical procedures are only complex in their sum but each step is simple in itself. Your hub amply and ably demonstrates this principle.

    • Free2writ3 profile image

      Free2writ3 5 years ago from Sharon Hill, Pennsylvania

      Very useful hub..Thanks alot.

    • profile image

      dravid 5 years ago

      thanks and nice post

    • profile image

      Monica 4 years ago

      Thank you so much for your simple breakdown on how to calculate a Standard Deviation both manually and using Excell. It was straight to the point and the example was quite helpful. I will now be able to help my sister understand the concept also.

      THANK YOU!!! :-)

    • profile image

      Robbi 4 years ago

      Thanks. This really helped me help my daughter with her maths homework.

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      @whowas.. thank you very much for the nice comment, it is great to receive encouragement and it is a great motivator to go and write articles that deliver some sort of usefulness to the reader. Thanks again !

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      @Sharon & Dravid... thanks very much for the comments

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      @Monica and Robbi... I am glad that you found this explanation to be of benefit... thanks very much for the comments :-)

    • profile image

      pakistan 4 years ago

      Thanks very thanks sir

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      Thank you, I am glad!

    • FreezeFrame34 profile image

      FreezeFrame34 4 years ago from Charleston SC

      Great and helpful! I took Algebra I and II, Geometry, Trig, and Honors Pre-Cal in high school as well as college classes, but never took Prob and Stats! This hub is easy to follow and I can use it to help my kids in the classroom!

    • anastasiaphillis profile image

      Anastasia Phillis 4 years ago from Chicago

      I teach standard deviation once every 2 months, and the excel stuff was nice. Good idea to add some poetry :)

    • pringoooals profile image

      Karina 4 years ago from Edinburgh

      Very informative and nicely explained. Well done!

    • Drax profile image
      Author

      des donnelly 4 years ago from NYC....

      @FreezeFrame... sorry for the slow response, I seem to have missed a whole raft of comments here... I am very glad that you will be able to use this hub in education in any way at all... many thanks :-)

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      @Anastasiaphillis... thanks for the comment, sorry for the slow response, poetry and mathematics actually go together very well, Einstein said;- "Pure mathematics is, in its way, the poetry of logical ideas."

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      @Pringoooals... again also apologies for the slow response, thanks very much for the comment.!

    • dinesh-varyani profile image

      dinesh-varyani 4 years ago

      Hi Drax,

      Its such a wonderful hub .... I am a Java Expert and write post regarding Java programs .... I am planning to write a Java program hub based on how to calculate standard deviation .... It will be dedicated to you ..... Thanks man .....

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      @dinesh-varyani... thanks very much for the comment !

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      Sweet 4 years ago

      Thanks for this, I missed this in class, your explanation is probably a lot easier to understand anyways!

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      that's.. Sweet... ;-)

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      Pleapagenna 4 years ago

      We helpful to acquire on top of life however of late I've established a new level of resistance.

    • Drax profile image
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      des donnelly 4 years ago from NYC....

      @Pleapagenna... life is full of resistance, this is a good thing :-)

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      Lindiwe Mazibuko 3 years ago

      Thank you very much for the information, i wanted these steps for the past two weeks and my tutor could not explain as clear as it is done on this site. Thanks again you have made my day and hope will done well on my exam.

    • Drax profile image
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      des donnelly 3 years ago from NYC....

      @Lindiwe Mazibuko.. thank you for taking the time to say so.. it is always lovely to receive feedback like this and I really hope that your exam went well... :-)

    • profile image

      gepeTooRs 15 months ago

      I will surely visit back for more –Great job!

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