Here are the shopping times (in minutes) for a sample of 5 shoppers at a particular clothing store ?

Question

40,25,33,43,39

Find the standard deviation of this sample of shopping times. Round your answer to at least two decimal places.

Answer 1

The mean is (40 + 25 + 33 + 43 + 39)/5 = 36.

40 - 36 = 4, and its square is 16.

25 - 36 = 11, and its square is 121.

33 - 36 = -3, and its square is 9.

43 - 36 = 7, and its square is 49.

39 - 36 = 3 and its square is 9.

Then their sum is 16 + 121 + 9 + 49 + 9 = 204.

Now divide by 1 minus the same size, which is 4.

So 204/4 = 51.  Finally take the square root to

get sqrt(51) = 7.14.