Homework 15

1.  Carter Motor Company claims that its new sedan, the Libra, will average no more than 32 miles per gallon in the city. Assuming that a hypothesis test to support this claim has been conducted and that the conclusion is to reject the null hypothesis, state the conclusion in nontechnical terms.

  There is not sufficient evidence to reject the claim that its new sedan, the Libra, will average no more than 32 miles per gallon in the city. 
  There is sufficient evidence to reject the claim that its new sedan, the Libra, will average no more than 32 miles per gallon in the city. 
  There is not sufficient evidence to support the claim that its new sedan, the Libra, will average no more than 32 miles per gallon in the city. 
  There is sufficient evidence to support the claim that its new sedan, the Libra, will average no more than 32 miles per gallon in the city. 

2.  A manufacturer considers his production process to be out of control when defects exceed 3%. In a random sample of 142 items, the defect rate is 9.1% but the manager claims that this is only a sample fluctuation and production is not really out of control. At the 10% level of significance, use the critical value method to test the manager’s claim.

Enter the test statistic. (Round your answer to nearest hundredth.)

3.   A manufacturer considers his production process to be out of control when defects exceed 4.6%. In a random sample of 117 items, the defect rate is 9.7% but the manager claims that this is only a sample fluctuation and production is not really out of control. At the 10% level of significance, use the p-value method to test the manager’s claim.

Enter the p-value. (Round your answer to nearest thousandth.)

4.   A medical school claims that more than 24% of its students plan to go into general practice. It is found that among a random sample of 25 of the school’s students, 28% of them plan to go into general practice. Find the P-value for a test to support the school’s claim. (Round your answer to nearest ten-thousandth.)

Homework 15 Answers

2.  A manufacturer considers his production process to be out of control when defects exceed 3%. In a random sample of 142 items, the defect rate is 9.1% but the manager claims that this is only a sample fluctuation and production is not really out of control. At the 10% level of significance, use the critical value method to test the manager’s claim.

Enter the test statistic. (Round your answer to nearest hundredth.)

Answer:  4.26