1. Which one of the following variables is not categorical?
► a) Age of a person
► b) Gender of a person: male or female
► c) Choice on a test item: true or false
► d) Marital status of a person (single, married, divorced, other)
Answer - a
2. Which of the following would be most likely to produce selection bias in a survey?
► a) Using questions with biased wording
► b) Only receiving responses from half of the people in the sample
► c) Conducting interviews by telephone instead of in person
► d) Using a random sample of students at a university to estimate the proportion of people who think the legal drinking age should be lowered
Answer - d
3. What is one of the distinctions between a population parameter and a sample statistic?
► a) A population parameter is only based on conceptual measurements, but a sample statistic is based on a combination of real and conceptual measurements.
► b) A sample statistic changes each time you try to measure it, but a population parameter Remains fixed
► c) A population parameter changes each time you try to measure it, but a sample statistic remains fixed across samples
► d) The true value of a sample statistic can never be known but the true value of a population parameter can be known.
Answer - b
► a) It cannot be concluded that the difference in activity caused a difference in the change in blood pressure because in the course of a year there are many possible confounding Variables
► b) Whether or not the difference was caused by the difference in activity depends on what Else, the participants did during the year.
► c) It cannot be concluded that the difference in activity caused a difference in the change in blood pressure because it might be the opposite, which the people with high blood pressure were more likely to read a book than to walk
► d) It can be concluded that the difference in activity caused a difference in the change in Blood pressure because of the way the study was done.
Answer - d
5. The two treatments in this study were?
► a) Walking for half an hour three times a week and reading a book for half an hour three Times a week
► b) Having blood pressure measured at the beginning of the study and having blood pressure measured at the end of the study.
► c) Walking or reading a book for half an hour three times a week and having blood pressure measured
► d) Walking or reading a book for half an hour three times a week and doing nothing.
Answer - a
This is a randomized experiment rather than an observational study because:
► a) Blood pressure was measured at the beginning and end of the study.
► b) The two groups were compared at the end of the study.
► c) The participants were randomly assigned to either walk or read, rather than choosing Their own activity
► d) A random sample of participants was used.
Answer - c
7. Which of the following is a confounding variable in this study?
► a) Exercise
► b) Lung capacity
► c) Smoking or not
► d) Occupation
Answer - a
Which of the following is the explanatory variable in this study?
► a) Exercise
► b) Lung capacity
► c) Smoking or not
► d) Occupation
Answer - d
* a) 50%
* b) 10%
* c) 5%
* d) 2%
Answer - b
10. Which one of these statistics is unaffected by outliers?
* a) Mean
* b) Inter-quartile range
* c) Standard deviation
* d) Range
Answer - b
11. A list of 5 pulse rates is: 70, 64, 80, 74, 92. What is the median for this list?
* a) 74
* b) 76
* c) 77
* d) 80
Answer - a
12. Which of the following would indicate that a dataset is not bell-shaped?
* a) The range is equal to 5 standard deviations.
* b) The range is larger than the inter-quartile range.
* c) The mean is much smaller than the median.
* d) There are no outliers.
Answer - c
* a) Teachers encourage people to get college degrees, so an increase in the number of teachers is causing an increase in the number of people with college degrees.
* b) Larger cities tend to have both more teachers and more people with college degrees, so the association is explained by a third variable, the size of the city.
* c) Teaching is a common profession for people with college degrees, so an increase in the number of people with college degrees causes an increase in the number of teachers.
* d) Cities with higher incomes tend to have more teachers and more people going to college, so income is a confounding variable, making causation between number of teachers and number of people with college degrees difficult to prove
Answer - b
* a) The x-variable explains 25% of the variability in the y-variable.
* b) The x-variable explains 25% of the variability in the y-variable.
* c) The x-variable explains 50% of the variability in the y-variable.
* d) The x-variable explains 50% of the variability in the y-variable.
Answer - a
15. What is the effect of an outlier on the value of a correlation coefficient?
* a) An outlier will always decrease a correlation coefficient.
* b) An outlier will always increase a correlation coefficient.
* c) An outlier might either decrease or increase a correlation coefficient, depending on where it is in relation to the other points
* d) An outlier will have no effect on a correlation coefficient.
Answer - c
16. One use of a regression line is?
* a) To determine if any x-values are outliers
* b) To determine if any y-values are outliers
* c) To determine if a change in x causes a change in y.
* d) To estimate the change in y for a one-unit change in x.
Answer - d
* a) A student who scored 0 on the midterm would be predicted to score 50 on the final exam.
* b) A student who scored 0 on the final exam would be predicted to score 50 on the mid term exam
* c) A student who scored 10 points higher than another student on the midterm would be predicted to score 5 points higher than the other student, did on the final exam
* d) Students only receive half as much credit (.5) for a correct answer on the final exam compared to a correct answer on the midterm exam
Answer - c
* a) 0.20
* b) 0.40
* c) 0.33
* d) 0.50
Answer - a
19. Among people with age under 30 what are the odds that they always exceed the speed limit?
* a) 1 to 2
* b) 2 to 1
* c) 1 to 1
* d) 50%
Answer - c
* a) 2.5
* b) 0.4
* c) 0.5
* d) 30%
Answer - a
* a) Where was the study conducted?
* b) How many students in the study participated in after-school sports?
* c) What is the baseline risk for getting asthma?
* d) Who funded the study?
Answer - c
* a) The baseline risk of getting asthma without participating in after-school sports
* b) The overall risk of getting asthma for the children in this study
* c) The relative risk of getting asthma for children who routinely participate in vigorous after-school sports on smoggy days and their non-athletic peers.
* d) All of the above could be computed
Answer - a
* a) Nearly symmetric
* b) Skewed to the left
* c) Skewed to the right
* d) Bimodal (has more than one peak).
Answer - c
24. The median of the distribution is approximately?
* a) -10 pounds
* b) 10 pounds
* c) 30 pounds
* d) 50 pounds
Answer - b
25. Most of the women in this sample felt that their actual weight was?
* a) About the same as their ideal weight
* b) less than their ideal weight.
* c) greater than their ideal weight.
* d) No more than 2 pounds different from their ideal weight
Answer - c
