Here's the solution for Standard Deviation (Grped Data) Prac Qn 3.
Notice that the histograms show evidence that grp B scores gather mostly around 50-90, whereas Grp A spread from 10 all the way to 100. This is a clear example of how standard deviation DOESN'T do its job as a measure of consistency.
In Statistics, which is a big branch of Maths, you'll find that you ought to use different measures to calculate and compare. It all depends on what kind of data has been gathered. It's a very big subject area. You'll know more when you enter JC, or if you take up Stats module in Poly Maths or Uni Maths... or, if you just surf the internet !
:)
