someone please explain Standard Deviation to me.

Question

First of all, an example; mean age of the children in a test is 12.93, with a standard deviation of .76.

Now, maybe I am just over thinking this, but everything I Google gives me this big convoluted explanation of what standard deviation is without addressing the kiddy pool I’m standing in.

Edit: you guys have been fantastic! This has all helped tremendously, if I could hug you all I would.

In: Mathematics

Answer 1

With a normal (bell-curve) distribution, 66% (IIRC) will have a result within one standard deviation from the mean, and 95% will have a result within two standard deviations.

So if a test had an average score of 85, and the standard deviation was 5, then you know the majority of the class got a score in the 80s, and very few had scores >95 or <75.