**1. Simpsons Paradox occurs when?**

* a) No baseline risk is given, so it is not know whether a a high relative risk has practical importance

* b) High relative risk has practical importance

* b) A confounding variable rather than the explanatory variable is responsible for a change in the response variable.

* c) The direction of the relationship between two variables changes when the categories of a confounding variable are taken into account.

* d) The results of a test are statistically significant but are really due to chance.

Answer - c

* a) Related in the population represented by the sample.

* b) Not related in the population represented by the sample

* c) Related in the sample due to chance alone

* d) Very important

Answer - a

* a) Hypothetical counts that would occur of the alternative hypothesis were true.

* b) Hypothetical counts that would occur if the null hypothesis were true

* c) The actual counts that did occur in the observed data

* d) The long-run counts that would be expected if the observed counts are representative.

Answer - b

* a) Marriage leads to better emotional health.

* b) Better emotional health leads to marriage.

* c) The more emotionally healthy someone is, the more likely are they to be married

* d) There are likely to be confounding variables related to both emotional health and marital status

Answer - d

**5. 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

**6. The median of the distribution is approximately?**

* a) -10 pounds

* b) 10 pounds

* c) 30 pounds

* d) 50 pounds

Answer - b

* a) Nearly symmetric

* b) Skewed to the left

* c) Skewed to the right

* d) Bimodal (has more than one peak).

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) 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

**11. 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) 0.20

* b) 0.40

* c) 0.33

* d) 0.50

Answer - a

* 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

**14. 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

**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

* 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

* 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

**18. 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

**19. 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

**20. Which one of these statistics is unaffected by outliers?**

* a) Mean

* b) Inter-quartile range

* c) Standard deviation

* d) Range

Answer - b

* a) 50%

* b) 10%

* c) 5%

* d) 2%

Answer - b

Which of the following is the explanatory variable in this study?

► a) Exercise

► b) Lung capacity

► c) Smoking or not

► d) Occupation

Answer - d

**23. Which of the following is a confounding variable in this study?**

► a) Exercise

► b) Lung capacity

► c) Smoking or not

► d) Occupation

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

**25. 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

► 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

**27. 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

**28. 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

**29. 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