A survey was done by Shop 'n' Bag supermarket headquarters. The management is concerned about the high turnover of stockers (you don't think those boxes and cans just magically appear, do you?). A sample of records was surveyed to see how many months stockers had been on the payroll. The results are shown below:
56 15 14 8 18 21 50 16 3 8 18 15 48 52 16 13 10 5
Find the value of the interquartile range (IQR).