Question 1. Which of the following is most appropriate to be plotted on the Y-axis of a histogram?

a) The scores on the dependent variable.

b) The levels of the independent variable.

c) Means and standard deviations.

d) The frequency of each score on the dependent variable.

Question 2. In a positively skewed distribution, which of the following is true?

a) You would have to have the actual data to answer this question.

b) The mean is greater than the median.

c) The mean is less than the median.

d) The mean is the same as the median.

Question 3. Which of the following measures of central tendency can be used to describe the average number of people with various eye colors?

a) Mode

b) Median

c) Range

d) Mean

Question 4. Conceptually, what is the standard deviation?

a) Half the difference between the highest and lowest scores in a distribution.

b) The difference between the highest and lowest scores in a distribution.

c) The average amount that the scores in a distribution differ from the mean.

d) The mean of the squared scores.

Question 5. A researcher shows that doctors who act more confidently are liked better by their patients, but only up to a point. If they act too confidently, their patients start to like them less. Which of the following best describes the correlation between doctor's level of confidence and patient's ratings of likability for the doctor?

a) There is no relationship between physician confidence and patient liking.

b) There is a negative relationship between physician confidence and patient liking.

c) There is a positive relationship between physician confidence and patient liking.

d) There is a nonlinear relationship between physician confidence and patient liking.

Question 6. Which of the following is true of outliers?

a) They should be included when calculating descriptive statistics but excluded when calculating inferential statistics.

b) They must be removed from the data set before calculating any statistics.

c) They must be included in all statistical analyses.

d) The researcher can choose to remove them before conducting statistical analyses, but their removal should have a reasonable justification.

Question 7. Which of the following is most clearly a statement about a statistical relationship between variables?

a) Prejudice continues to be a significant problem in this country.

b) "Pain-Away" is more effective at treating headaches than its nearest competitor.

c) The average score on the Stanford-Binet Intelligence Scale is 100 points.

d) About one-third of Americans have a psychological disorder at some time in their lives.

Question 8. What is the main reason researchers perform null hypothesis testing?

a) To decide whether a relationship that exists in a sample represents a real relationship in the population.

b) To decide whether the independent variable caused changes in the dependent variable.

c) So they can use statistics to test the null hypothesis.

d) To decide how strong a sample relationship is.

Question 9. Dr. Kerry conducted a study which found a "statistically significant" relationship between the number of books children read at home during the year and their overall GPA in school. The result is based on a sample of 20,000 children. Which of the following is true?

a) The relationship must be a causal one.

b) The relationship is extremely strong.

c) The relationship could be extremely weak.

d) Dr. Kerry failed to reject the null hypothesis.

Question 10. What does it mean if the result of your study is "not statistically significant"?

a) The result may be due to sampling error.

b) The result represents a "real" result that is true in the population.

c) The result is unimportant.

d) You reject the null hypothesis.

Question 11. Dr. Sanjay analyzed data he collected from elderly adults who were trying a new medication to treat dementia. Some received the real drug while others received a placebo in this double-blind study. When Dr. Sanjay conducted an independent t test on this data, he calculated an actual t value of 2.36 and found the critical t value was 1.725. Which of the following is true?

a) His p value is greater than .05.

b) He should reject the null hypothesis.

c) He should not reject the null hypothesis.

d) He should have conducted a paired-samples t test.

Question 12. When a study lacks statistical power, the researcher is in danger of which of the following?

a) Committing a Type I error.

b) Committing a sampling error.

c) Committing both a Type I and Type II error.

d) Committing a Type II error.

Question 13. Dr. Moraff wants to compare scores on a math test before and after she teaches students how to use some special mnemonic devices to help them remember tricky math rules. What kind of analysis should she conduct?

a) Independent t test

b) Chi-squared test

c) One-way ANOVA

d) Paired-samples t test

Question 14. A research methods student carries out a null hypothesis test. She performs all the statistical analyses correctly and makes the correct decision to reject the null hypothesis. Which of the following statements is also correct?

a) She may have committed a Type II error.

b) She conducted a study which lacks enough power to detect a statistically significant difference between levels of the independent variable.

c) She may have committed a Type I error.

d) She could not have committed a Type I or Type II error.

Question 15. Dr. Ward compares anxiety scores for patients who took her new drug (which is very expensive to produce) and an old drug (which is much less expensive to produce). She determines that there is a statistically significant difference between the scores of patients who took the two different drugs and submits the results of her study to the FDA with the expectation that they will approve marketing of the new medication. What else needs to be considered?

a) The cost of producing the new drug may prevent these results from having practical significance.

b) Practical significance can only be assessed after the medication is FDA approved.

c) Whether or not she was able to reject the null hypothesis in her research study.

d) The number of patients who participanted in the study may have prevented these results from demonstrating practical significance.