A two-tailed hypothesis test is being used to evaluate a treatment effect with α = .05.If the sample data produce a z-score of z = -2.24,what is the correct decision?
A)Reject the null hypothesis and conclude that the treatment has no effect
B)Reject the null hypothesis and conclude that the treatment has an effect
C)Fail to reject the null hypothesis and conclude that the treatment has no effect
D)Fail to reject the null hypothesis and conclude that the treatment has an effect

Question

Quizplus · Accepted Answer

The correct decision is to reject the null hypothesis and conclude that the treatment has an effect. This is because the calculated z-score of 102.24 is greater than the critical values of ±1.96 for a two-tailed hypothesis test with α = .05. This means that the probability of obtaining such an extreme result under the null hypothesis is very low, and we can reject the null hypothesis in favor of the alternative hypothesis that the treatment has an effect.

A Two-Tailed Hypothesis Test Is Being Used to Evaluate a Treatment