Question: Contaminated chicken, second course. The January 2007 Consumer Reports study described in Exercise also found that 15% of the 525 broiler chickens tested were infected with Salmonella.

a) Are the conditions for creating a confidence interval satisfied? Explain.

b) Construct a 95% confidence interval.

c) Explain what your confidence interval says about chicken sold in the United States.

Exercise: Contaminated chicken. In January 2007 Consumer Reports published their study of bacterial contamination of chicken sold in the United States. They purchased 525 broiler chickens from various kinds of food stores in 23 states and tested them for types of bacteria that cause food-borne illnesses. Laboratory results indicated that 83% of these chickens were infected with Campylobacter.

a) Construct a 95% confidence interval.

b) Explain what your confidence interval says about chicken sold in the United States.

c) A spokesperson for the U.S. Department of Agriculture dismissed the Consumer Reports finding, saying, "That's 500 samples out of 9 billion chickens slaughtered a year. With the small numbers they [tested], I don't know that one would want to change one's buying habits." Is this criticism valid? Explain.