Find the standard deviation, s, of sample data summarized in the frequency distribution table below by using the formula below, where x represents the class midpoint, f represents the class frequency, and n represents the total number of sample values. Also, compare the computed standard deviation to the standard deviation obtained from the original list of data values, 11.1.



Interval



20-26

27-33

34-40

41-47

48-54

55-61

62-68

Frequency

1

4

3

1

12

32

33