In the past,the mean running time for a certain type of flashlight battery has been 9.0 hours.The manufacturer has introduced a change in the production method and wants to perform a hypothesis test to determine whether the mean running time has changed as a result.

Question

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We need a two-sided hypothesis test to determine whether the mean running time has changed, which means we want to test if it has increased or decreased. The null hypothesis would be that there is no change in the mean running time (μ = 9.0), and the alternative hypothesis would be that there is a change in the mean running time (μ ≠ 9.0). Therefore, we need a two-sided hypothesis test.

In the Past,the Mean Running Time for a Certain Type