The accounts manager of a large retail store is investigating the number of days that customers take to pay their invoices, the normal period being 30 days. An inspection of the payment records of 30 randomly- selected customers, revealed the following payment pattern. 35 42 34 27 32 30 24 33 27 36 30 38 26 32 28 28 39 23 17 20 31 29 30 24 25 29 31 30 19 34 1.1 Using 7 classes, each of width 4, construct a frequency distribution of the above data. Let 18 be the upper limit of the initial class. 1.2 Using the grouped data determined in 1.1 above, estimate each of the following. 1.2.1 middle quartile. 1.2.2 70th percentile 1.2.3 mode. 1.3 Calculate the coefficient of variation and interpret the result