A two-tailed hypothesis test is being used to evaluate a treatment effect with ? = .05.If the sample data produce a z-score of z = -2.24, then 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 critical z-scores for a two-tailed test with α = 0.05 are approximately ±1.96. Since -2.24 is beyond -1.96, we reject the null hypothesis, indicating the treatment has an effect.

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