Compute the Standard Deviation of a Variable from Raw Data
-81, 75, 44, 63, 42, 30, 64, 76, 88
A) 19.9
B) 17.8
C) 350.2
D) 315.2

Question

Quizplus · Accepted Answer

The standard deviation is calculated by first finding the mean of the data, then the squared differences from the mean, and finally taking the square root of the average of those squared differences. For this data set, the mean is 62.33, the sum of squared differences from the mean is 3558, and dividing by the number of observations (9) gives a variance of 395.33. The square root of the variance is approximately 19.9, which is the standard deviation.