stat2.docx

2 The Questions

A major restaurant chain claims the mean waiting time for customers is no more than 9 minutes. A random sample of 35 customers was selected and the waiting time recorded. The mean waiting time was found to be 9.95 minutes with a standard deviation of 2.00 minutes. Perform the appropriate test of hypothesis.

Use this information to answer Questions 1 - 9.

1. What is the appropriate null hypothesis? 2. What is the appropriate alternative hypothesis? 3. What is the value of the test statistic? 4. What is the appropriate rejection region? (Use α = 0.05.) 5. What is the appropriate conclusion?

6. What is the p-value for this problem?

7. Find a 90% confidence interval for the true mean waiting time.

8. Interpret the interval in Exercise 7.

9. Based in the interval in Exercise 7, can one reject a claim that the true mean waiting time is 9.5 minutes?

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The life of a battery used in a designer dog leash is assumed to be approximately normally distributed. A random sample of 10 such batteries is selected and placed on accelerated life test yielding the following results (measured in hours):

80 73 92 82 77 75 88 76 95 105

The manufacturer of the battery claims the mean battery life is 75 hours. Use this information to answer Questions 10 - 15.

10. What is the appropriate null hypothesis?

11. What is the appropriate alternative hypothesis?

12. What is the appropriate test to use for this problem? (a) z-test (b) t-test (c) F-test (d) Binomial Test

13. What is the value of the test statistic?

14. What is the p-value for this problem?

15. Based on the p-value, what is the appropriate conclusion?