Question

Another measure of variation is variance, which equals . Find the variance and standard deviation of the data set. Round to the nearest tenth.
8, 9, 5, 7, 4, 11

Answer 1

determine the mean

determine the square of the difference of the mean from each data point

take the average of the squares

Answer 2

mean = 22/3, multiply the set by 3 to make life simpler

{24, 27, 15, 21, 12, 33}, now subtract 22 from each

{ 2, 5, 7, 1, 10, 11}, square them

{ 4, 25, 49, 1, 100, 121} and divide them by 3^2

{ 4/9, 25/9, 49/9, 1/9, 100/9, 121/9}

the variance of the population is the average of that set