The quality control manager at a cell phone battery factory needs to determine whether the mean life of a large shipment of batteries is equal to the specified value of 375 hours. The process standard deviation is known to be 100 hours. A random sample of 64 batteries indicates a sample mean of 350 hours.
-The null and alternative hypotheses to test whether the shipment meets the specified value is _____.

Question

Quizplus · Accepted Answer

The null hypothesis (H0) is typically a statement of no effect or no difference, and it is what we seek evidence against. In this case, we want to test if the mean life of the batteries is equal to the specified value of 375 hours. Therefore, H0: µ = 375. The alternative hypothesis (Ha) is what we suspect might be true instead, which in this case is that the mean life is not equal to 375 hours, hence Ha: µ ≠ 375.

The Quality Control Manager at a Cell Phone Battery Factory