Ted Olson, director of the company Overnight Delivery,is worried because of the number of letters of first class that hiscompany has lost. These letters are transported in airplanes andtrucks, due to that, mister Olson has classified the lost lettersduring the last two years according to the transport in which theletters were lost. The data is as follows:
Number of cards lost in (month) | J | F | M | A | M | J | J | A | S | O | N | D |
Truck | 4 | 5 | 2 | 3 | 2 | 1 | 3 | 5 | 4 | 7 | 0 | 1 |
Airplane | 5 | 6 | 0 | 2 | 1 | 3 | 4 | 2 | 4 | 7 | 4 | 0 |
Mister Olson will investigate only one department,either aerial o ground department, but not both. He will open theinvestigation in the department which has the most number of lostletters per month, find:
26.- The expectation quadratic value of lost letters permonth for truck.
27.- The expectation quadratic value of lost letters permonth for airplane.
28.- The variance value of lost letters per month fortruck.
29.- The variance value of lost letters per month forairplane.
