Compute the Standard Deviation of a Variable from Raw Data
-8, 7, 7, 7, 12, 11, 14, 16, 14
A) 3.5
B) 3.3
C) 12.5
D) 11.1

Question

Quizplus · Accepted Answer

The standard deviation is calculated by first finding the mean (average) of the data set, then calculating the variance by finding the average of the squared differences from the Mean, and finally taking the square root of the variance. For the given data set: Mean = (8 + 7 + 7 + 7 + 12 + 11 + 14 + 16 + 14) / 9 = 96 / 9 = 10.67. Then, calculate each data point's squared difference from the mean, average those squared differences, and take the square root. The correct calculation results in a standard deviation of approximately 3.5.