Question

1. A study is conducted to test the hypothesis that a new drug is effective in lowering blood pressure. Which of the following would be a type I error?

		Concluding the that the drug is effective when it is not effective
		Concluding the drug is not effective when it is effective
		Saying the null hypothesis is false
		None of the above

2. A study is conducted to see if there is a difference in the prevalence in smoking between male and female college students. Which of the following would be a type II error?

		Concluding that there is not a difference in prevalence between genders when there is a difference.
		Concluding that there is a difference between genders when there is not a difference.
		The research hypothesis is false
		None of the above

Answer 1

1. Type I error is the error of rejecting the null hypothesis when it is true. Here the null hypothesis will be that there is no difference in the effectiveness of new drug and old drug. Hence type I error would be to conclude that the drug is effective when it is not effective. Thus, 1st option is correct.

2. Type II error is the error of accepting the null hypothesis when it is false. Here the null hypothesis will that there is no difference in the prevalence of smoking between the two groups. Hence type II error would be to conclude that there is not a difference in prevalence between genders when there is a difference. Thus, 1st option is correct.