Statistics chapter 7

The power of the decision-making process is ______. a. stated by an alpha level b. the likelihood of rejecting a false null hypothesis c. the same as a null finding d. the likelihood of committing a Type I error

b. the likelihood of rejecting a false null hypothesis

Which of the following is not one of the four steps to hypothesis testing? a. state the hypotheses b. identify hypothetical data c. set the criteria for a decision d. compute the test statistic

b. identify hypothetical data

A researcher reports that the standard deviation in Population A is sigma = 2.3 and the standard deviation in Population B is sigma = 4.3. Which population is associated with the highest power to detect an effect? a. Population A b. They are associated with the same level of power. c. Population B

a. Population A

A researcher conducts two studies. Each study was a one-sample z test. Both studies placed the rejection region in both tails and measured the same sample mean. The beat level in Study 1 was larger than the beta level used in Study 2. Which study is associated with greater power to detect an effect? a. Study 2 b. They are associated with the same level of power. c. Study 1

a. Study 2

A researcher directly controls for the probability of a ______, but does not directly control for the probability of a ______. a. Type I error; Type II error b. Type II error; beta level c. Type II error; Type I error d. Type I error; alpha level

a. Type I error; Type II error

The one-sample z test is a hypothesis test used to test hypotheses ______. a. concerning a single population with a known variance b. concerning at least one population c. concerning the variance in a population d. all of these

a. concerning a single population with a known variance

When reporting the results of a one-sample z test using APA format, the ______ does not need to be reported. a. critical values b. effect size c. test statistic d. p value

a. critical values

Based on the effect size conventions, d = 0.90 is a ______. a. large effect size b. medium effect size c. small effect size

a. large effect size

Based on the effect size conventions, d = 0.60 is a ______. a. medium effect size b. small effect size c. large effect size

a. medium effect size

In Step 2 of hypothesis testing, researchers state a level of significance to minimize the probability of ______. a. rejecting a true null hypothesis b. retaining a false null hypothesis c. inflating the power of a decision d. all of these

a. rejecting a true null hypothesis

The criterion for a decision regarding the value stated in a null hypothesis is set by the ______. a. probability value b. both A and B c. p value d. level of significance

d. level of significance

What are the two decisions that researchers can make in hypothesis testing? a. both A and B are correct b. accept or reject the null hypothesis c. retain or reject the null hypothesis

c. retain or reject the null hypothesis

A researcher obtains z = 1.80 for a one-sample z test. What is the decision for this test at a .05 level of significance? a. It depends on whether the test is one-tailed or two-tailed. b. to retain the null hypothesis c. to reject the null hypothesis

a. It depends on whether the test is one-tailed or two-tailed.

A researcher believes that increasing attention given to children will improve mean academic performance. Therefore, the alternative hypothesis should be ______. a. mean academic performance will increase b. mean academic performance will not change c. mean attention will increase d. mean academic performance will decrease

a. mean academic performance will increase

Given the following values: sigma = 10, M = 8, sigmaM = 0.5, conduct a one-sample z test at a .05 level of significance. What is the decision for a two-tailed test? a. to retain the null hypothesis b. to reject the null hypothesis c. There is not enough information since the sample size is not given.

b. to reject the null hypothesis

______ allows researchers to describe (1) how far mean scores have shifted in the population or (2) the percentage of variance that can be explained by a given variable. a. Effect size b. Significance c. Power d. Probability

a. Effect size

A researcher obtains z = 3.98 for a one-sample z test. If her decision is to retain the null hypothesis, then what do you know about her decision? a. Her decision resulted in a Type III error. b. Her decision was inconclusive. c. both A and B d. Her decision was based on a two-tailed test.

a. Her decision resulted in a Type III error.

Which of the following statements regarding the null hypothesis is true? a. The null hypothesis always makes statements about a population parameter. b. A decision in hypothesis testing is made about the alternative hypothesis, not the null hypothesis. c. The null hypothesis is the only hypothesis stated in hypothesis testing. d. all of these

a. The null hypothesis always makes statements about a population parameter.

The probability of committing a Type I error is stated by ______ and the probability for committing a Type II error is stated by ______. a. alpha; beta b. beta; alpha c. a p value; a p value d. the power; the power

a. alpha; beta

A researcher reports that the size of an effect in Population A is d = 0.10 and the effect size in Population B is d = 0.34. Which population is associated with greater power to detect an effect? a. They are associated with the same level of power. b. Population B c. Population A

b. Population B

Increasing sample size will ______. a. increase the alpha level b. increase the likelihood of committing a Type I error c. increase the power of the decision d. all of these

c. increase the power of the decision

What is the typical level of significance for a hypothesis test in behavioral research? a. .50 b. .001 c. .10 d. .05

d. .05

A researcher reports the following result for a one-sample z test at a .05 level of significance: z = 1.88, p = -.06 (d = .25). Is this result significant? a. No, because the effect size is small hypothesis. b. Yes, because the effect size is large hypothesis. c. Yes, the decision is to reject the null hypothesis. d. No, the decision is to retain the null hypothesis.

d. No, the decision is to retain the null hypothesis.

If a researcher obtains a null finding, then what is the decision? a. They failed to make a decision. b. They incorrectly rejected the null hypothesis. c. They correctly rejected the null hypothesis. d. They correctly retained the null hypothesis.

d. They correctly retained the null hypothesis.

A measure of the size of an effect in a population is called ______. a. effect size b. significance c. power d. probability

a. effect size

A professor finds that the average SAT score among all students attending his college is 1150 +/- 150 (mu +/- sigma). He polls his class of 25 students and finds that the average SAT score is 1,200. Suppose he computes a one-sample z test at a .05 level of significance. What is his decision? a. to reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test b. to retain the null hypothesis c. to reject the null hypothesis for a two-tailed test, but to retain the null hypothesis for an upper-tailed test d. to reject the null hypothesis

a. to reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test

Given the following values: mu = 6.0, M = 7.6, n = 36, sigma = 6, conduct a one-sample z test at a .05 level of significance. For a one-tailed test, upper-tail critical, what is the decision? a. to retain the null hypothesis b. to reject the null hypothesis c. There is not enough information since the sample size is not given.

a. to retain the null hypothesis

Which of the following best describes the p value? a. It is the same as an alpha level. b. It is a conditional probability. c. Its value must be greater than .05 to reject the null hypothesis. d. all of these

b. It is a conditional probability.

A researcher selects a sample of 36 students from a school population with a mean IQ of 100 and standard deviation of 12. She determines that the mean IQ in this sample is 104. Assuming she computes a one-sample z test at a .05 level of significance, what is the decision for a two-tailed test? a. Retain the null hypothesis; IQ scores in this sample are the same as those in the population. b. Reject the null hypothesis; IQ scores in this sample are significantly higher than those in the population. c. There is not enough information to make a decision.

b. Reject the null hypothesis; IQ scores in this sample are significantly higher than those in the population.

A researcher computes a one-sample z test in two studies. Both studies used the same alpha level, placed the rejection region in both tails, and measured the same sample mean. The researcher selects a sample of 30 participants in Study 1 and decides to retain the null hypothesis. She selects a sample of 60 participants in Study 2 and decides to reject the null hypothesis. Which of the following is the best explanation for why the decision was different in Study 1 and Study 2? a. The different decisions in Study 1 and Study 2 are not possible because all values were the same. b. The different decisions in Study 1 and Study 2 are possible because the second test was associated with greater power to detect an effect. c. The different decisions in Study 1 and Study 2 are not possible because the researcher tested the same hypothesis. d. The different decisions in Study 1 and Study 2 are due to an error the researcher made in the first hypothesis test.

b. The different decisions in Study 1 and Study 2 are possible because the second test was associated with greater power to detect an effect.

A researcher computes a test statistic and finds that the p value for this test is .03. What does this result mean? a. The probability of committing a Type II error if we reject the null hypothesis is 3%. b. There is a 3% likelihood of obtaining the test statistic value, if the null were true. c. The probability of committing a Type I error if we retain the null hypothesis is 3%. d. There is a 3% likelihood that the researcher's hypothesis is correct.

b. There is a 3% likelihood of obtaining the test statistic value, if the null were true.

A researcher reports that scores were higher than the mean in the population, z = 1.60, p = .05 (d = .14). If this was a test at a .05 level of significance, then what value must be incorrectly reported? a. the test statistic b. the p value c. the alpha level d. the effect size

b. the p value

A researcher obtains z = 1.45 for a one-sample z test. What is the decision for this test at a .05 level of significance? a. It depends on whether the test is one-tailed or two-tailed. b. to retain the null hypothesis c. There is not enough information to make a decision. d. to reject the null hypothesis

b. to retain the null hypothesis

A researcher reports that the size of an effect in some population is d = 0.88. Which of the following is an appropriate interpretation for d? a. Mean scores were significant by 0.88 points in the sample. b. The effect observed in the population was significant. c. Mean scores shifted 0.88 standard deviations in the population. d. Mean scores were significant by 0.88 points in the population.

c. Mean scores shifted 0.88 standard deviations in the population.

Is a one-sample z test reported differently for one-tailed and two-tailed tests? a. It depends on whether the results were significant. b. It can be reported differently when the effect size is large. c. No, the same values are reported. d. Yes, only significant results for a two-tailed test are reported.

c. No, the same values are reported.

When a researcher decides to retain the null hypothesis because the rejection region was located in the wrong tail, this is called a ______. a. Type I error b. Type II error c. Type III error d. correct decision

c. Type III error

A method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called ______. a. level of significance b. random sampling c. hypothesis testing d. guessing

c. hypothesis testing

In hypothesis testing, a researcher can never ______. a. make decisions about the null hypothesis b. know the likelihood of obtaining a sample mean if the null hypothesis were true c. prove that his or her hypothesis is correct d. compute a test statistic before making a decision

c. prove that his or her hypothesis is correct

Suppose a researcher wants to make sure that the probability of committing a Type I error is less than 5%. How can the researcher control for this? a. place the rejection region in both tails b. set the value for a Type II error at .05 c. set the alpha level at .05 d. both B and C

c. set the alpha level at .05

Hypothesis testing is also called ______. a. random testing b. effect size c. significance testing d. Type III error

c. significance testing

Based on the effect size conventions, d = 0.18 is a ______. a. medium effect size b. large effect size c. small effect size

c. small effect size

If the value of the test statistic is in the rejection region, then ______. a. p < .05 b. the decision is to reject the null hypothesis c. the value of the test statistic is larger than the critical value d. all of these

d. all of these

In hypothesis testing, a researcher's decision ______. a. is based on a probability b. depends on the level of significance for a hypothesis test c. can be to retain or reject the null hypothesis d. all of these

d. all of these

Researchers state a level of significance in terms of an alpha level. The alpha level indicates ______. a. the probability of committing a Type I error b. the probability of incorrectly rejecting the null hypothesis c. the probability value for the rejection region d. all of these

d. all of these

Which of the following is a scenario in which increasing sample size will increase power ______. a. when the effect size is small b. when the effect size is large c. when the probability of a Type I error is small d. all of these

d. all of these

A researcher conducts a study, but has low power to detect an effect. Which of the following is one way in which the research can increase power? a. make the alpha level smaller b. conduct the study again with the same sample size c. study a population with a larger standard deviation d. increase the sample size

d. increase the sample size

The first step to hypothesis testing requires that a researcher ______. a. conduct a study b. compute a test statistic c. make a decision d. state the hypotheses

d. state the hypotheses

A researcher obtains z = 2.04 for a one-sample z test. What is the decision for this test at a .05 level of significance? a. to retain the null hypothesis b. It depends on whether the test is one-tailed or two-tailed. c. There is not enough information to make a decision. d. to reject the null hypothesis

d. to reject the null hypothesis

A researcher obtains z = -6.45. What is the decision for a one-tailed test, upper-tail critical, at a .05 level of significance? a. It depends on the sample size. b. to reject the null hypothesis c. There is not enough information to make a decision. d. to retain the null hypothesis

d. to retain the null hypothesis

A professor gives an exam in which the mean score is 78 points. She gives another exam to test whether or not scores change. In this example, the null hypothesis is ______. a. u? ‚ 78 b. M ?0 ‚ 78 c. M = 78 d. u = 78

d. u = 78