The following data set indicates the number of customers per day who utilised a (5) local ATM, over a random sample of twenty days:

23 23 24 38 32 42 42 28 37 36 35 36 33 40 33 27 34 39 35 34

Construct a grouped frequency distribution table for this data set. Your table should include columns indicating the frequency count values (f) and the percentage frequencies (%f) for each class. The total for each of the latter columns should also be included. Use the classes 20 -< 25; 25 -< 30; and so on. For all probability questions below, give final probability answers as percentages to two decimal places, unless otherwise indicated.