in a survey, 20 people were asked how many magazines they had purchased during the previous year. the results are shown below. 6 15 3 36 25 18 12 18 5 30 24 7 1 22 33 24 19 4 12 9 a) construct a frequency distribution table using 4 classes. construct relative frequency table. b) construct a histogram, frequency polygon, and stem-and-leaf diagram for the data