Assignment

1. Last month the waiting time at the drive through window of a fast-food restaurant was 3.7 minutes. The franchise has installed a new process intended to reduce waiting time. After the installation, a random sample of 64 orders is selected. The sample mean waiting time is 3.57 minutes with a sample standard deviation of 0.8 minutes. At a 5% level of significance, is there sufficient evidence that the population mean waiting time is now less than 3.7 minutes? What is your conclusion?

2. In a survey of 1,040 adults conducted by American Express Incentive Services, 563 responded that they would prefer being given $100 rather than a day off from work. At a 5% level of significance, is there enough evidence from this survey to conclude that more than half of all adults would rather have $100 than a day off? What is your conclusion? What is the p-value for this test?

3. A tire manufacturer produces tires that are believed to have a mean life of at least 25,000 miles when the production process is working correctly. Based on past experience, the population standard deviation of the lifetime of the tires is 3,500 miles. Assume a level of significance for testing of 5%, and a random sample of 100 tires:

A) What would be the consequences of making a Type II error in this problem?

B) Compute the Probability of making a Type II error if the true population mean is 24,000 miles.

Please Note: A hypothesis test answer must contain: a Null and an Alternate Hypothesis, a computed value of the test statistic, a critical value of the test statistic, a Decision , and a Conclusion.