Educational Psychology / Unit 12 EDP 1142 short lesson, about 20 seconds
Range, Variance and Standard Deviation
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The idea
Variability describes how spread out scores are: the range is the highest score minus the lowest; the variance is the average squared distance from the mean; and the standard deviation, its square root, gives the typical distance from the mean.
In practice
Scores from 55 to 95 have a range of 40.
Where people slip
Two classes with the same mean can differ greatly in spread.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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