Question

1. The manager of a restaurant in a large city claims that waiters working in all restaurants in his city earn an average of more than $150 in tips per week. A random sample of 25 waiters selected from restaurants of this city yielded a mean of $155 in tips per week with a standard deviation of $28. Assume that the weekly tips for all waiters in this city have a normal distribution.

Let μ denote the mean tips earned by waiters. Calculate the t statistic. Round your answer to the nearest hundredth (e.g., 1.23 or -1.23).

2. The manager of a restaurant in a large city claims that waiters working in all restaurants in his city earn an average of more than $150 in tips per week. A random sample of 25 waiters selected from restaurants of this city yielded a mean of $155 in tips per week with a standard deviation of $28. Assume that the weekly tips for all waiters in this city have a normal distribution.

Let μ denote the mean tips earned by waiters. Calculate the degree of freedom.

3. You were asked to test if the mean number of hours spent working per week by college students who hold jobs is different from 20 hours using a t test. Suppose the t statistic for this test is 1.86 and the degree of freedom is 25. Calculate the p-value for this test. Round your answer to the nearest 10,000 (e.g., 0.1234).

4. In a Gallup poll conducted July 7-10, 2014, 45% of Americans said that they actively try to include organic foods into their diets. In a recent sample of 2100 Americans, 1071 said that they actively try to include organic foods into their diets. You want to test whether the current percentage of all Americans who way that they actively try to include organic foods into their diets is different from 45%.

Calculate the z statistic for this test. Round your answer to the nearest 100th (e.g., 1.23).

Answer 1