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
Mean (or average) gives you a measure of a ‘center’ (in one definition) of a number of measurements.
Standard deviation (SD) gives you a measure of how much those measurements are spread out around that mean, i.e., how much the measurements “deviate” from that average. If you calculate two more values — mean plus SD and mean minus SD — it tells you that 2/3 of your measurements are within that range.
So, the smaller the standard deviation, the closer 2/3 of the measurements are to the mean.
In your example above, rounding off to make things simpler, 2/3 of the measurements are well within the age range of 12-14.
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