so234 ch 8

Do sex education classes and free clinics that offer counseling for teenagers reduce the number of pregnancies amongteenagers? The appropriate test of this hypothesis would be... a. a one-tailed test. b. a two-tailed test. c. cross-sectional. d. participant observation.

a. a one-tailed test.

All tests of hypothesis are based on the assumption that... a. the null hypothesis is false and should be rejected. b. the observed difference is important. c. the null hypothesis is true. d. Type I errors are more serious than Type II errors.

a. the null hypothesis is false and should be rejected.

If we reject a null hypothesis of "no difference" at the 0.05 level... a. the odds are 20 to 1 in our favor that we have made a correct decision. b. the null hypothesis is true. c. the odds are 5 to 1 in our favor that we have made a correct decision. d. the research hypothesis is true.

a. the odds are 20 to 1 in our favor that we have made a correct decision.

A one-tailed test of significance could be used whenever... a. the researcher can predict a direction for the difference. b. the researcher feels like it. c. the null hypothesis is thought to be true. d. the alpha level exceeds 0.10.

a. the researcher can predict a direction for the difference.

In tests of significance, if the test statistic falls in the critical region, we may conclude that... a. the population distribution is normal. b. the null hypothesis can be rejected. c. the research hypothesis is true. d. our sample size was too small.

b. the null hypothesis can be rejected.

Given that the null hypothesis is actually true, the probability of Type II error is... a. 0.00 b. 0.05 c. 1.00 d. the alpha level.

a. 0.00

Which assumption must be true in order to justify the use of hypothesis testing? a. Random sampling b. Interval-ratio level of measurement c. Very large samples d. Samples have been stratified

a. Random sampling

The research and null hypotheses BLANK each other. a. contradict b. complement c. amplify d. rescind

a. contradict

The research hypothesis (H1) typically states what the researcher expects to find and... a. contradicts the null hypothesis. b. verifies on the null hypothesis. c. modifies the null hypothesis. d. is unrelated to the null hypothesis.

a. contradicts the null hypothesis.

In a one-tailed test of hypothesis, the entire BLANK should be placed in either the upper or lower tail of the BLANK. a. critical area, sampling distribution b. sample mean, population distribution c. Z score, critical area d. sampling distribution, sample distribution

a. critical area, sampling distribution

If the critical region begins at Z (critical) = ± 2.56 and the test statistic is - 2.50, we... a. fail to reject the null hypothesis. b. reject the null hypothesis. c. cannot make a decision because the test statistic is so close to the critical region. d. change the alpha level.

a. fail to reject the null hypothesis.

Republicans average 1.4 children while the state as a whole averages 1.7 children. The Z score computed in this test is 0.78 and the alpha level is 0.05. Therefore, the difference in size of family... a. is due to random chance. b. does not reflect the situation of all Republicans. c. is significant. d. All of the above

a. is due to random chance.

In terms of Z scores, the absolute value of the critical value for a one tailed test is... a. less than it is for a two tailed test. b. greater than it is for a one tailed test. c. greater for lower tails than upper tails. d. greater for upper tails than lower tails.

a. less than it is for a two tailed test.

Which of the following is NOT an assumption required for a test of hypothesis with a single sample mean? a. A representative sample b. Sample size (N) larger than 1,000 c. Normal sampling distribution d. Interval-ratio level of measurement

b. Sample size (N) larger than 1,000

Which of the following must be normally distributed in order to proceed with hypothesis testing of means and proportions? a. The sample distribution b. The sampling distribution c. The population distribution d. Both the sample distribution and the population distribution

b. The sampling distribution

In terms of hypothesis testing, "significance" refers to the... a. difference between an independent and dependent variable. b. difference between the sample and population values. c. difference between the two independent variables. d. difference between our observed and our predicted outcomes.

b. difference between the sample and population values.

In most cases, a researcher sets out to... a. prove the null hypothesis. b. disprove the null hypothesis. c. prove the research hypothesis. d. disprove the research hypothesis.

b. disprove the null hypothesis.

If we reject a null hypothesis which is in fact true, we... a. have made a correct decision. b. have made a Type I error. c. have made a Type II error. d. should have used a one-tailed test.

b. have made a Type I error.

In hypothesis testing, the BLANK is the critical assumption, the assumption which is actually tested. a. research hypothesis b. null hypothesis c. assumption of a normal sampling distribution d. assumption that the sample was randomly selected

b. null hypothesis

According to the text, the Federal Drug Administration tests new drugs based on the assumption that the... a. sample has not been selected according to EPSEM. b. null hypothesis ("the drug is not effective") is true. c. level of measurement is less than ordinal. d. sample is neither biased nor efficient.

b. null hypothesis ("the drug is not effective") is true.

The critical region is... a. the area under the curve that contains "non-rare" events. b. the area under the curve that includes those values of a sample statistic that will lead to rejection of the null. c. a confidence interval. d. a law that states that the shape of the sampling distribution is normal.

b. the area under the curve that includes those values of a sample statistic that will lead to rejection of the null.

Comparing one- and two-tailed tests (with a constant alpha level and sample size), the probability of rejection will be higher for... a. the two-tailed test. b. the one-tailed test, if you have correctly predicted the direction of the difference. c. neither, the probability of rejection does not change. d. the test with the most conservative test statistic.

b. the one-tailed test, if you have correctly predicted the direction of the difference.

A researcher is interested in the effect that neighborhood crime-watch efforts have on the crime rate in the inner city, buthe is unwilling to predict the direction of the difference. The appropriate test of hypothesis would be... a. one-tailed. b. two-tailed. c. descriptive. d. symmetrical.

b. two-tailed.

A sample of people attending a professional football game averages 13.7 years of formal education while thesurrounding community averages 12.1. The difference is significant at the .05 level. What could we conclude? a. The null hypothesis should be accepted. b. The research hypothesis should be rejected. c. The sample is significantly more educated than the community as a whole. d. The alpha level is too low.

c. The sample is significantly more educated than the community as a whole.

In tests of significance, if the test statistic does NOT fall in the critical region, we... a. conclude that the population distribution is normal. b. reject the null hypothesis. c. fail to reject the research hypothesis. d. conclude that our alpha level was too low.

c. fail to reject the research hypothesis.

Given the same alpha level, the one-tailed test... a. makes it harder to reject the Ho. b. does not affect the probability of rejecting the Ho. c. makes it more likely that Ho will be rejected. d. is less dependable than the two-tailed test.

c. makes it more likely that Ho will be rejected.

An alpha of 0.01 means that a decision to BLANK the null hypothesis has a BLANK in 100 chance of being incorrect. a. accept, 1 b. fail to reject, 1 c. reject, 1 d. reject, 100

c. reject, 1

When we decide on a value for alpha, we are... a. defining the likelihood of accepting the alternative hypothesis. b. establishing whether the test will be one or two tailed. c. setting the probability of committing a Type I error. d. setting the probability of a one-tailed test.

c. setting the probability of committing a Type I error.

The probability of Type I error is... a. .01 b. .05 c. the alpha level. d. beta.

c. the alpha level.

All other things being equal, with which of the following alpha levels would we be most likely to reject the null hypothesis? a. .01 b. .001 c. .05 d. .10

d. .10

To conduct a test of hypothesis with a single sample mean, we must assume... a. the sampling distribution is normal. b. random sampling. c. interval-ratio level of measurement. d. All of the above

d. All of the above

The null hypothesis in the one sample case is a statement of... a. agreement with the research hypothesis. b. rejection. c. acceptance. d. no difference.

d. no difference.

In order to conduct a test of hypothesis with means or proportions, the sampling distribution must be... a. skewed. b. large. c. bimodal. d. normal.

d. normal.

With alpha set at .05, the Critical Region for a two-tailed test would begin at ± 1.96. In a one-tailed test at the same alpha level the Critical Region would begin at... a. ± 1.96. b. ± 2.58. c. ± 2.30. d. ± 1.65.

d. ± 1.65.