The grades of of 20 calculus students is listed below:
25, 27, 25, 32, 27, 36, 45, 29, 26, 20, 48, 54, 60, 48, 38, 43, 38, 23, 65, 63
Make a stem-and-leaf plot of this data.
Draw a frequency table and a histogram for this data with the first class starting at 20 and class-widths of 10.
What is the frequency of the second class?