4.19 Combining the cost-per-serving data for high-fiber cereals rated very good and those rated good from the previous exercise gives the following data set:

46 49 62 41 19 77 71 30 53 53 67 43 48 28 54

a. Compute the quartiles and the interquartile range for this combined data set. (Hint: See Example 4.9.)

b. Compute the interquartile range for just the cereals rated good. Is this value greater than, less than, or about equal to the interquartile range computed in Part (a)?