Calculate the sample standard deviation for this data since

Question

The following frequency table summarizes the distances in miles of 100 patients from a regional hospital.

Distance (miles)         Frequency

0-2                              40

2-4                              25

4-6                             20

6-8                            10

8-10                             5

Calculate the sample standard deviation for this data (since it is a case of grouped data with classes, use group or class midpoints in the formula in place of X values).