Hypothesis Testing with Known Population Standard Deviation

What is the claim made by the sports car manufacturer regarding the fuel injection system?

• It lasts 60 months before replacement.

• It lasts 45 months before replacement.

• It lasts 50 months before replacement.

• It lasts 48 months before replacement.

What is the null hypothesis in this hypothesis test?

• The mean lifespan is not equal to 48 months.

• The mean lifespan is greater than 48 months.

• The mean lifespan is less than 48 months.

• The mean lifespan is equal to 48 months.

What type of test is being conducted in this example?

• Two-sided test

• Right-tailed test

• Non-directional test

• Left-tailed test

What is the calculated test statistic (z-star) in this example?

• 1.28

• 0.99

• -1.28

• -0.99

What conclusion is drawn from the hypothesis test?

• Accept the alternative hypothesis.

• The test is inconclusive.

• Fail to reject the null hypothesis.

• Reject the null hypothesis.