The operations manager of a large airport is concerned with the problem of having adequate personnel to offer individual assistance to handicapped passengers during rush hours. Data were collected on the number of requests for assistance during 20 randomly selected rush hours and revealed the information shown in Table.

Hour no. 1 2 3 4 5 6 7 8 9 10 No. of requests 40 42 42 30 38 48 42 44 37 38 Hour no. 11 12 13 14 15 16 17 18 19 20 No. of requests 49 47 34 57 42 52 56 44 50 48