(3) To compare two types of coating for resistance to corrosion, 15 pieces of pipe were coated with each type of coating. Two pipes, one with each type of coating, were buried together and left for the same length of time at 15 different locations, providing a natural pairing of the observations. Corrosion for the two types of coating was measured by two variables: maximum depth of pit in thousands of an inch (Depth) and number of pits (Number). A partial description of the dataset is given below, and the data are available in the file 'coatings.DAT' on Canvas. (25 pts) At 5% significance level, test whether the two coatings differ in their effect on corrosion