The following data shows the weekly sales claimed by some door-to-door salespeople selling sets of reference books:

5 8 10 7 6 3 8 12 8 3 12 15
6 8 7 5 3 18 19 15 13 14 18 24
Determine whether any of the claims should be investigated as suspicious

Work out the 5 number summary

Min=3
Q1=6
Median=8
Q3=14.5
Max= 24

IQR=Q3-Q1
=14.5 - 6
=8.5

Work out if 24 is an outlier or not.

x-Q3>1.5*IQR
24-14.5>1.5*8.5
9.5>12.75
24 is an outlier