Question

1. Which of the following statements is correct?

	a.	For a given level of significance, the critical value of Student's t increases as n increases.
	b.	A test statistic of t = 2.131 with d.f. = 15 leads to a clear-cut decision in a two-tailed test at d = .05.
	c.	It is harder to reject the null hypothesis when conducting a two-tailed test rather than a one-tailed test.
	d.	If we desire α = 0.10 then a p-value of 0.13 would lead us to reject the null hypothesis.

2. A TV special said there is a 10 per cent incidence of sexually transmitted disease (STD) among all U.S. teens. A reporter for the Rockville Bugle, looking for a story, surveyed 260 randomly chosen teenagers, and found that 39 had been to a clinic for STD treatment. Use a right-tail test at α = .05. The p-value is (use table C-2 tail side)

	a.	.0501
	b.	.0314
	c.	2.258
	d.	.0036

3. Which is not true of p-values?

	a.	When they are small, we want to reject Ho.
	b.	They must be specified before the sample is taken.
	c.	They show the chance of Type I error if we reject Ho.
	d.	They do not require α to be specified a priori.

4. A TV special said there is a 10 per cent incidence of sexually transmitted disease (STD) among all U.S. teens. A reporter for the Rockville Bugle, looking for a story, surveyed 260 randomly chosen teenagers, and found that 39 had been to a clinic for STD treatment. Use a right-tail test at α = .05. The calculated test statistic is

	a.	2.687
	b.	2.758
	c.	.0256
	d.	2.258

5. The probability of rejecting a true null hypothesis increases as the sample size increases.

True

False

6. In a two-tailed hypothesis test with α = .05, a test statistic of t = 1.813 with d.f. = 15 leads one to reject the null hypothesis of a statistical test.

True

False

Answer 1