These data show the ring sizes for a sample of 8 men. 12 10 11.5 11.5 12 9 9 11 What is the best approximation of the standard deviation for the ring size data?

The population size of the above data is 8, that is N=8

The mean (average) = (12 + 10 + 11.5 + 11.5 + 12 + 9 + 9 + 11) / 8

= 10.75

Standard deviation is the square root of variance, it is one of the measures of central dispersion, that is a measure of by how much the values in the data set are likely to differ from the mean.

In this case, Standard deviation, s = √ (∑ (x-m) ²) / (n-1)

= 1.172

Thus, best approximation of the standard deviation is 1.17