JAMB 2010 · UTME · Q48

Find the standard deviation of 2, 3, 5 and 6.

Worked solution (try it first)

The mean is $\frac{2 + 3 + 5 + 6}{4} = 4$ .
The squared deviations are 4, 1, 1, 4, which add up to 10.
The variance is $\frac{10}{4} = \frac52$ , so the standard deviation is $\sqrt{\frac52}$ , option A.