A researcher evaluates a treatment effect using a two-tailed hypothesis test wit

Question

A researcher evaluates a treatment effect using a two-tailed hypothesis test with alpha =.05, and the decision is to reject the null hypothesis. If the researcher switched to a one-tailed test using the same sample and alpha level, what decision would be made? What if he still uses a two-tailed test but changes alpha to .01? You completed a hypothesis test using alpha=.05, and based on the evidence from the sample, your decision is to fail to reject the null hypothesis. If the treatment actually does have an effect, did you make any error? If so, what can you do to avoid making this error?

Explanation / Answer

Solution:-

a)

i) If the researcher swith to one tailed test using the same sample and alpha level, there would be no change in the decision, the Null hypothesis would be rejected.

When we switch to one tailed test from two tailed test, p-value become half.

p value is already less than 0.05, thatswgy we have rejected the null hypothesis, now it is halfed so it will remain less than 0.05, so there would be no change in the decision, the Null hypothesis would be rejected.

ii) If he still use the two tailed test but changes a alpha to 0.01, then there would be followig cases:-

If p value is less than 0.01, then reject the null hypothesis.

If p value is less than 0.05 and more than 0.01 than accept the null hypothesis.

b) We make a type II error, i.e incorrectly retaining a false null hypothesis. We can increase the sample size to avoid making this type of error.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.