A civil engineer is interested in several designs for a drainage canal used to divert floodwaters from around a city. The drainage times of a reservoir attached to each of five different channel designs obtained from a series of experiments using similar initial flow conditions are given in the following table.

a. Can you conclude that there is a difference in the mean drainage times for the different channel designs?
b. Which pairs of designs, if any, can you conclude to differ in their mean drainage times?

Channel Type Drainage time (min) 41.4 43.4 50.0 41.2 37.7 49.3 52. 37.3 32.6 33.7 34.8 22.5 27.3 29.9 32.3 24.8 44.9 47.2 48.5 37.1