The Quick Change Oil Company has a number of outlets. The numbers of oil changes at the Oak Street outlet in the past 20 days 

as follows:

The data are to be organized into a frequency distribution using 5 classes.

b. What class interval would you suggest? (Round the final answer to the nearest whole number.) 

c. What lower limit would you recommend for the first class?

d. Organize the information into a frequency distribution and determine the relative frequency distribution. (Round the "Relative frequency" answers to 2 decimal places.)

e. Comment on the shape of the distribution. (Enter the intervals in ascending order.)

The greatest concentration is in classes  up to  and  up to  .