Null Hypothesis Significance Testing

Which of the following might be a research hypothesis that could be tested with a one-sample z-test? a. The mean alertness score of individuals differs between when they consume 0 mg of caffeine and when they consume 90 mg of caffeine. b. There is no relationship between outdoor temperature and minutes of aerobic exercise per week. c. The mean level of happiness for a group of students in a college sorority is different than the known mean level of happiness for the whole campus. d. There is a relationship between a person's score on a measure of extraversion and their score on a measure of happiness.

The mean level of happiness for a group of students in a college sorority is different than the known mean level of happiness for the whole campus

In null hypothesis significance testing, if a result is unlikely under the ____ hypothesis, then we infer support for the ____ hypothesis. a. null; null b. null; alternative c. alternative; alternative d. alternative; null

null; alternative

When the p-level associated with your calculated test statistic is smaller than the alpha, you should: a. fail to reject the null hypothesis. b. reject the research hypothesis. c. reject the null hypothesis. d. accept the null hypothesis.

reject the null hypothesis

In null hypothesis significance testing, we use the null distribution to gauge the probability that a result could be due to: a. researcher bias. b. an independent variable. c. a placebo effect. d. sampling error.

sampling error

Select an appropriate α-level for conducting a hypothesis test. a. 0.50 b. 0.00 c. 0.05 d. 0.80

0.05

Select the example of a harmful outcome of a Type II error. a. Individuals buy and consume drugs that are not actually effective and have numerous side effects. b. Pharmaceutical companies are charging large amounts of money for medications that are ineffective. c. Studies that find a very large difference are viewed as more important than those that find a small difference. d. A patient never receives a medication that could extend her life by months because during clinical trials no difference in longevity was found.

A patient never receives a medication that could extend her life by months because during clinical trials no difference in longevity was found

While conducting a one-sample z-test, researchers identified critical z values of ±1.96 (two-tailed test, with α = .05) and calculated a z-statistic of 1.53. What would be the appropriate hypothesis test decision? a. Reject the null hypothesis, because the test statistic is in the rejection region. b. Fail to reject the null hypothesis, because the test statistic is positive. c. Fail to reject the null hypothesis, because the test statistic is not in the rejection region. d. Reject the null hypothesis, because the test statistic is larger than alpha.

Fail to reject the null hypothesis, because the test statistic is not in the rejection region

Select the appropriate version of the one-tailed null hypothesis in notation based on the research hypothesis stated in words below. Alternative hypothesis: The average exam grade for students who rewrite their notes as their primary form of studying is lower than the average exam grade of students who come up with new examples of concepts as their primary form of studying. Population 1 is the students who rewrite their notes and population 2 is the students who come up with examples. a. H0: μ1 ≤ μ2 b. H0: μ1 < μ2 c. H0: μ1 ≥ μ2 d. H0: μ1 > μ2

H0: μ1 ≥ μ2

A psychologist has reason to believe that people who drink coffee (Condition 1) will report a higher average number of sleep disturbances compared to those who do not drink coffee (Condition 2). Which are the appropriate alternative and null hypotheses? a. H1: μ1 = μ2; H0: μ1 ≠ μ2 b. H1: μ1 < μ2; H0: μ1 ≥ μ2 c. H1: μ1 ≠ μ2; H0: μ1 ≥ μ2 d. H1: μ1 > μ2; H0: μ1 ≤ μ2

H1: μ1 > μ2; H0: μ1 ≤ μ2

Why might a researcher choose to run a two-tailed hypothesis test instead of a one-tailed hypothesis test? a. The researcher wants to test for an effect in either direction. b. The researcher is certain the effect is in the predicted direction. c. The researcher wants to make it more likely that the null hypothesis will be rejected. d. The researcher is only interested in one direction of an effect.

The researcher wants to test for an effect in either direction

Researchers were interested in testing for a difference between the mean SAT score of students in an after-school enrichment program and the known mean SAT score for students in 2019. After conducting a two-tailed, one-sample z-test, researchers decided to reject the null hypothesis. What is the appropriate conclusion? a. The after-school enrichment program is not an effective way to increase SAT scores. b. There is a statistically significant difference in the mean SAT scores between students in an after-school enrichment program and students who completed the SAT in 2019. c. Students in an after-school enrichment program have higher mean SAT scores than those in a before-school enrichment program. d. There is not a statistically significant difference in the mean SAT scores between students in an after-school enrichment program and students who completed the SAT in 2019.

There is a statistically significant difference in the mean SAT scores between students in an after-school enrichment program and students who completed the SAT in 2019

Researchers were interested to know if there were differences in the average time to complete an exam before and after students learned a test-taking technique. Select the appropriate two-tailed null hypothesis. a. There is a difference in average time to complete an exam for students before they learned a test-taking technique and after they learned a test-technique. b. Students who learn a test-taking technique do not have a faster average time to complete an exam compared to students who have not learned a test-taking technique. c. There is no difference in average time for students to complete an exam before they learned a test-taking technique versus after they learned a test-technique. d. Students who learn a test-taking technique have a faster average time to complete an exam compared to students who have not learned a test-taking technique.

There is no difference in average time for students to complete an exam before they learned a test-taking technique versus after they learned a test-technique.

Based on their statistical findings, Mueller and Oppenheimer (2014) concluded that students who take notes longhand perform better on conceptual questions than those who take notes with a laptop. It is possible that the researcher's conclusion is actually a(n) _____ error. a. Type I b. statistically significant c. impractical d. Type II

Type I

In which scenario would you reject the null hypothesis? a. When the obtained test statistic is a small number b. When the obtained test statistic is more extreme than the critical value c. When the obtained test statistic is the same as the critical value d. When the obtained test statistic is not more extreme than the critical value

When the obtained test statistic is more extreme than the critical value

The null distribution is: a. a distribution with one value, zero. b. the population from which the control group is sampled. c. almost always positively skewed. d. a sampling distribution.

a sampling distribution

The probability of failing to reject the null hypothesis (statistical decision) when the null is actually false (population truth) is equal to: a. alpha (α). b. 1 － β. c. 1 － α. d. beta (β).

beta (β)

A researcher runs a two-tailed hypothesis test with α = 0.05. Based on her data, she fails to reject the null that there is no difference in math scores based on the time of day the test is taken. If this decision is a Type II error, then the truth in the population would be that: a. students only sometimes perform better when a math test is taken in the morning. b. there is a difference in math scores based on the time of day the test is taken. c. there is no difference in math scores based on the time of day the test is taken. d. math tests should be administered in the morning hours.

there is a difference in math scores based on the time of day the test is taken

The probability of making a Type I error is: a. denoted as β. b. higher with two-tailed tests. c. typically set at .05 by researchers. d. only applicable if a researcher fails to reject the null hypothesis.

typically set at .05 by researchers

Identify the critical z values for a two-tailed, one-sample z-test with alpha = .10, or 10%. a. −2.326 and 2.326 b. −1.645 and 1.645 c. −1.960 and 1.960 d. −1.282 and 1.282

−1.645 and 1.645