A data set on monthly expenditures (rounded to the nearest dollar) incurred on fast food by a sample of 500 households has a minimum value of $3 and a maximum value of $147. Suppose we want to group these data into six classes of equal widths.
a. Assuming that we take the lower limit of the first class as $1 and the upper limit of the sixth class as $150, write the class limits for all six classes.
b. Determine the class boundaries and class widths.
c. Find the class midpoints.