Which of the following choices is the standard deviation of

Which of the following choices is the standard deviation of the sample shown here? 19, 20, 21, 22, 23 square root 2 21 2 square root 2.5 2.5

Solution

19 , 20 , 21 , 22 , 23

Mean = 21

standard deviation = {[(19 - 21)² + (20 - 21)² + (21 - 21)² + (22 - 21)^{2 +} + (23 - 21)²]/5}

==> [ (4 + 1 + 0 + 1 + 4)/5]

==> (10/5)

==> 2

Hence standard deviation is 2 (option A)