Tim McGrath has recorded the post positions of 300 winning horses in his favorite sport. He wants to know if there is a relationship between post position and winning a race or whether the winners are equally distributed. Use a .95 confidence interval.

Two companies which make diet soda hold the majority share of the market, while others share the remainder. Both companies ran major advertising campaigns. Two hundred customers were surveyed after the campaigns and asked their preferences. Was there any change as a result? Use a .95 confidence interval.

A company has been accused of biased hiring practices. According to census data, the percentages of Whites in the community in which the company is located is 70%, the percentage of Blacks is 12%, and the percentage of Hispanics is 18%. The following table gives the number of company employees in each category. Use a .95 confidence interval.

A professor says she typically grades on a curve, giving about 5% A's, 25% B's, 40% C's, 25% D's, and 5% F's. Following is the grade distribution from this semester. Does it follow the announced pattern? Use a .95 confidence interval.