What is the standard deviation for the following set of scores: 20,24,26,22,18,16,18?

A) 12.95
B) 3.60
C) 6.55
D) 24

The standard deviation is calculated by finding the square root of the average of the squared deviations from the mean. For this set, the mean is 20.86, and the squared deviations from the mean are 0.74, 9.86, 26.45, 1.30, 8.16, 23.52, and 8.16 respectively. The average of these squared deviations is 12.9, and the square root of 12.9 is approximately 3.60.