Quality control engineers are trying to improve the number of unpopped kernels in their company's microwave popcorn.Changes to the oil have recently been made,so the engineers are testing the hypothesis
: μ = 25 against
: μ

Question

Quality control engineers are trying to improve the number of unpopped kernels in their company's microwave popcorn.Changes to the oil have recently been made,so the engineers are testing the hypothesis 
: μ = 25 against 
: μ < 25.

Quizplus · Accepted Answer

The hypothesis is testing whether the mean number of unpopped kernels is less than 25, indicating a desire to reduce the number of unpopped kernels. This is a lower-tailed test, as the engineers are interested in whether the mean number of unpopped kernels is significantly lower than the current level. The null hypothesis is that the mean number of unpopped kernels is equal to 25, and the alternative hypothesis is that the mean number of unpopped kernels is less than 25. Therefore, the best choice is C, lower-tailed.

Quality Control Engineers Are Trying to Improve the Number of Unpopped