7.5 The Variance and Standard Deviation. Definitions. The Formula. Let’s try! Find the mean Calculate the variance. Variance measures the dispersal of the information. Basically, how spread out is the data? If the variance is small: The data is concentrated about the mean
Find the mean
Calculate the variance
Calculate the variance of this information.
Statistic used to measure the dispersal about the mean
The reason this is good is because Var(X) is based upon the X values, whereas the standard deviation is “generic”