Colored string preferred by chickens. Animal behaviorists have discovered that the more domestic chickens peck at objects placed in their environment, the healthier the chickens seem to be. White string has been found to be a particularly attractive pecking stimulus. In one experiment, 72 chickens were exposed to a string stimulus.

Instead of white string, blue string was used. The number of pecks each chicken took at the blue string over a specified interval of time was recorded. Summary statistics for the 72 chickens were x = 1.13 pecks and s = 2.21 pecks

(Applied Animal Behaviour Science, Oct. 2000).

a. Use a 99% confidence interval to estimate the population LO6 mean number of pecks made by chickens pecking at blue string. Interpret the result.

b. Previous research has shown that m = 7.5 pecks if chickens are exposed to white string. Based on the results you found in part

a, is there evidence that chickens are more apt to peck at white string than blue string? Explain.