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
We have a good idea of what average (mean) means, so think of it like this: Standard deviation is the average difference from the average.
It’s just a measure of spread. The higher the standard deviation, the more spread out the data is from the mean.
If you look at the formula, it is the average of the square of the difference, which penalises large differences more.
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.
Standard deviation = how volatile something is.
If the value doesn’t change much = low standard deviation and vice-versa.
Thank you for coming to my TED talk.
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