Question: Identify any potential sources of bias in the following study.
From a poll of people who recently bought cold medicine at all stores of a large drugstore chain, investigators concluded that the mean time between colds for all Americans is 5.6 months.
What sources of bias, if any, might this study have?
Answer Options:
A. Both selection and participation bias
B. Selection bias only
C. Participation bias only
D. There is probably no bias in the study.
Answer: A. Both selection and participation bias
Question: Identify any potential sources of bias in the following study.
In order to determine the opinions of people in the 18- to 27-year age group on controlling illegal immigration, researchers survey 2500 National Guard members in this age group.
What sources of bias, if any, might this study have?
Answer Options:
A. Participation bias only
B. Selection and participation bias
C. Selection bias only
D. There is probably no bias in the study.
Answer: B. Selection and participation bias
Question: The headline “Drugs shown in 98 percent of movies” accompanied a news story that described a “government study” claiming that drug use, drinking, or smoking was depicted in 98% of the top movie rentals. Discuss whether the headline accurately represents the story.
Answer Options:
A. The headline refers to drugs whereas the story refers to “drug use, drinking, or smoking.” The headline is very misleading because the term “drugs” is generally considered to consist of drugs other than cigarettes or alcohol. Also, all movies consist of more than just the top movie rentals.
B. The headline is downplaying the results presented in the story, because the government produced the study.
C. The headline is exaggerating the results given in the story. The headline uses a bigger figure for the amount of drugs in movies than the figure given in the story.
D. The headline appears to accurately represent the news story.
Answer: A. The headline refers to drugs whereas the story refers to “drug use, drinking, or smoking.” The headline is very misleading because the term “drugs” is generally considered to consist of drugs other than cigarettes or alcohol. Also, all movies consist of more than just the top movie rentals.
Question: Discuss the differences between the following questions, each of which could be the basis for a statistical study.
What percentage of Internet dates lead to marriage?
What percentage of marriages begin with Internet dates?
Answer Options:
A. The percentage of marriages beginning with Internet dates can be accurately measured while the percentage of Internet dates that lead to marriage cannot be accurately measured.
B. The questions are too different to compare.
C. The questions have different populations.
D. The percentage of marriages beginning with Internet dates would be an observation while the percentage of Internet dates that lead to marriage would be an experiment.
Answer: C. The questions have different populations.
Question: 14. Testing whether the slope of the population regression line could be zero is equivalent to testing whether the population ________ could be zero.
Answer Options:
a. standard error of estimate
b. prediction interval
c. y-intercept
d. coefficient of correlation
Answer: d. coefficient of correlation
Question: 15. A multiple regression equation includes 4 independent variables, and the coefficient of multiple determination is 0.64. How much of the variation in y is explained by the regression equation?
Answer Options:
a. 80%
b. 16%
c. 32%
d. 64%
Answer: d. 64%
Question: 12. A computer statistical package has included the following quantities in its output: SST = 50, SSR = 35, and SSE = 15. How much of the variation in y is explained by the regression equation?
Answer Options:
a. 49%
b. 70%
c. 35%
d. 15%
Answer: b. 70%
Question: Independent variables in a regression equation should NOT be mutually exclusive.
Answer: False
Question
P-value is the smallest level of α at which to reject Ho.
Correct Answer: True
Question: The usual objective of regression analysis is to predict/estimate the value of one variable when the value of another variable is known.
Answer: True
Question: Correlation analysis is concerned with measuring the strength of the relationship between two variables
Answer: True
Question: In the least squares model, the explained sum of squares is always smaller than the regression sum of squares.
Answer: False
Question: The sample correlation coefficient and the sample slope will always have the same sign
Answer: True
Question: When small values of Y tend to be paired with small values of X, the relationship between X and Y is said to be inverse.
Answer: False
Question: When we reject a true null hypothesis, we commit a Type I error.
Answer: True
Question: Decide whether the following statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain your reasoning.
My bar chart contains more information than yours, because I made my bars three-dimensional.
Answer Options:
A. The statement makes sense because making the bars three-dimensional makes the graph easier to read and increases the amount of information that can be read from it.
B. The statement does not make sense because making the bars three-dimensional does not necessarily mean that information was added. It could mean that only the appearance of the graph was changed.
C. The statement makes sense because making the bars three-dimensional means that more information was used to create a third dimension in the graph.
D. The statement does not make sense because making the bars three-dimensional makes the graph harder to read and reduced the amount of information that can be read from it.
Answer: B. The statement does not make sense because making the bars three-dimensional does not necessarily mean that information was added. It could mean that only the appearance of the graph was changed.
Question: Decide whether the following statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain your reasoning.
There’s been only a very slight rise in our stock price over the past few months, but I wanted to make it look dramatic so I started the vertical scale from the lowest price rather than from zero.
Answer Options:
A. The statement does not make sense because reducing the range of the vertical axis to just fit the data will decrease the relative size of the variation in the data.
B. The statement makes sense because reducing the range of the vertical axis to just fit the data will increase the relative size of the variation in the data.
C. The statement does not make sense because changing the axis cannot change the data that is being displayed.
D. The statement makes sense because increasing the range of the vertical axis to contain all of the data will increase the relative size of the variation in the data.
Answer: B. The statement makes sense because reducing the range of the vertical axis to just fit the data will increase the relative size of the variation in the data.
Question: Which of the following would be considered a symptom?
Answer Options:
A. blood pressure reading of 150/90 mm Hg
B. body ache and chills
C. fever of 39 °C
D. heart rate of 120 bpm
Answer: B. body ache and chills
Question: According to Watson, the future of psychology lies in:
Answer Options:
A. Studying the mind.
B. Exploring consciousness.
C. Analyzing sensations.
D. Observing and measuring behavior.
E. Understanding emotions.
Answer: D. Observing and measuring behavior.
Question: Watson believes that introspection:
Answer Options:
A. Provides reliable scientific data.
B. Is the best method for studying the mind.
C. Should be the focus of psychology.
D. Is too subjective to be useful.
E. Offers valuable insights into behavior.
Answer: D. Is too subjective to be useful.
Question: For Watson, the goal of behaviorism is:
Answer Options:
A. To describe mental processes.
B. To explore internal experiences.
C. To predict and control behavior.
D. To understand consciousness.
E. To analyze sensations.
Answer: C. To predict and control behavior.
Question: Watson asserts that behaviorism should:
Answer Options:
A. Focus on the mind.
B. Discard the study of behavior.
C. Adopt the methods of introspection.
D. Concentrate on observable actions.
E. Prioritize the analysis of sensations.
Answer: D. Concentrate on observable actions.