When +1.645 is used as the critical value instead of ±1.96,
A)the total probability of the region of rejection is decreased.
B)the total probability of the region of rejection is increased.
C)the region of rejection is all placed in the positive tail.
D)the region of rejection is all placed in the negative tail.

Question

Quizplus · Accepted Answer

When the critical value is changed from ±1.96 to +1.645, the region of rejection is shifted to the positive tail only. This means that the probability of rejecting the null hypothesis (Type I error) for a given level of significance (alpha) when the alternative hypothesis is true (power) is reduced. However, the total probability of the region of rejection remains the same, as the area under the curve beyond the critical value is unchanged. Therefore, the correct answer is C.

When +1645 Is Used as the Critical Value Instead of ±1