When a computed z value (for a test for differences between two percentages), 4.21, is larger than the standard z value, 1.96, then this amounts to:
A) support for the null hypothesis; the two percentages are different
B) no support for the null hypothesis; the two percentages are NOT different
C) support for the null hypothesis, the two percentages are NOT different
D) no support for the null hypothesis; the two percentages are different
E) None of the above; a z value is inappropriate for testing the differences between two percentages.

Question

Quizplus · Accepted Answer

A computed z value larger than the standard z value indicates that the difference between the two percentages is statistically significant and unlikely to have occurred by chance, providing evidence against the null hypothesis which assumes no difference between the two percentages. Therefore, there is no support for the null hypothesis, and the correct answer is D, no support for the null hypothesis; the two percentages are different.

When a Computed Z Value (For a Test for Differences