Refer to the Applied Animal Behaviour Science (October 2000) study of domestic chickens exposed to a pecking stimulus, presented in Exercise. Recall that the average number of pecks a chicken takes at a white string over a specified time interval is known to beµ= 7.5 pecks. In an experiment in which 72 chickens were exposed to blue string, the average number of pecks was x = 1.13 pecks, with a standard deviation of s = 2.21 pecks.

a. On average, are chickens more apt to peck at white string than at blue string? Conduct the appropriate test of hypothesis, using α = .05.

b. Compare your answer to part a with your answer to Exercise 7.21 b.

c. Find the p -value for the test and interpret it.