It depends upon the validity and study. Some studies are not practical but they interest someone at least. And no, it doesn't mean that the 5th person enjoyed the experience. It just means they didn't hate it. It could be their 6th root canal and they are used to the experience. It is all about reading the data. Most people skew statistical data to fit their views when the data doesn't support their views at all. It's depressing to see at times.