Suppose we are testing the difference between two proportions at the 0.05 level of significance. If the computed z is -1.07, what is our decision?
A) Reject the null hypothesis.
B) Do not reject the null hypothesis.
C) Take a larger sample.
D) Reserve judgment.

Question

Quizplus · Accepted Answer

The computed z value (-1.07) does not exceed the critical value at the 0.05 level of significance (which would be -1.96 for a two-tailed test), so we do not have enough evidence to reject the null hypothesis. Also, taking a larger sample might not necessarily change the decision, since the z-value depends on the sample proportion and sample size, and the difference between the proportions being tested. Therefore, the best choice is B, which is to not reject the null hypothesis.

Suppose We Are Testing the Difference Between Two Proportions at the 0.05