Q.Calculate the standard deviation of the following values:
5, 10, 25, 30, 50.

For the values 5, 10, 25, 30, 50: mean = 24, the squared deviations add up to 1270, variance = 1270 / 5 = 254, and the standard deviation = square root of 254 = about 15.94.

This is a 5-mark measures-of-dispersion problem in the AP Intermediate 2nd-year Economics statistics unit. Standard deviation is found by the actual-mean method as the square root of the mean of the squared deviations from the arithmetic mean.

Step 1 — Find the mean

Mean = (5 + 10 + 25 + 30 + 50) / 5 = 120 / 5 = 24.

Step 2 — Find the deviations from the mean and square them