Student grade point averages (GPAs) are calculated by assigning a number to each letter grade earned, with A = 4, B = 3, C = 2, D = 1 and F = 0, then finding the average. A student proposes using the median of the numbers instead and calls this medGPA. A student has taken five courses (all an equal number of credit hours) and the grades were A, A, F, B, A. The usual GPA for these grades is 3.0 . Should the student prefer using the median (medGPA)?
a. No, because medGPA is F = 0 for this student.
b. It doesn't matter, because medGPA is also B = 3.0 for this student.
c. Yes, because medGPA is A = 4.0 for this student.
d. No, because if the student takes one more course and gets an A or B, the usual GPA will go up but the medGPA will stay the same.
Q. 2The five numbers in a five-number summary are the
a. lowest value, mean, median, mode, and the highest value.
b. lowest value, lower margin of error, median, upper margin of error, and the highest value.
c. lowest value, lower quartile, median, upper quartile, and the highest value.
d. lowest value, 2nd lowest value, middle value, 2nd highest value, and the highest value.
Q. 3Which of the following is true about a dotplot and a five-number summary?
a. A dotplot displays all of the individual responses while a five-number summary does not.
b. A five-number summary displays all of the individual responses while a dotplot does not.
c. Both a dotplot and a five-number summary display all of the individual responses.
d. Neither a dotplot nor a five-number summary displays all of the individual responses.
Q. 4Which of the following is not a component of Statistics as defined in Chapter 1?
a. Procedures and principles for gathering data
b. Procedures and principles for making decisions when faced with uncertainty
c. Procedures and principles for analyzing data and information
d. Procedures and principles for turning uncertainty into certainty
Q. 5A randomized experiment was done by randomly assigning each participant either to walk for half an hour three times a week or to sit quietly reading a book for half an hour three times a week. At the end of a year the change in participants' blood pressure over the year was measured, and the change was compared for the two groups. If a statistically significant difference in blood pressure change at the end of a year for the two activities was found, then
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 lots of 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, that 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.
Q. 6A randomized experiment was done by randomly assigning each participant either to walk for half an hour three times a week or to sit quietly reading a book for half an hour three times a week. At the end of a year the change in participants' blood pressure over the year was measured, and the change was compared for the two groups. 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.
Q. 7A randomized experiment was done by randomly assigning each participant either to walk for half an hour three times a week or to sit quietly reading a book for half an hour three times a week. At the end of a year the change in participants' blood pressure over the year was measured, and the change was compared for the two groups. 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.
Q. 8Suppose you were to read about a study showing that people who sleep less than five hours a night have twice as much risk of a premature death as people who sleep seven or eight hours a night.Which of the following is not an example of a possible confounding variable in this study?
a. Medications a person is taking.
b. The amount of alcohol a person drinks in the evening.
c. The amount of stress a person is under in their work.
d. The amount of sleep a person gets per night.
Q. 9Suppose you were to read about a study showing that people who sleep less than five hours a night have twice as much risk of a premature death as people who sleep seven or eight hours a night.The baseline risk in this context is
a. the risk of premature death for people who sleep less than five hours a night.
b. the risk of premature death for people who sleep seven or eight hours a night.
c. the risk of premature death for all people.
d. the risk of premature death at the beginning of the study for those in the study.
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