6) In a clinical trial of 2088 subjects treated with a certain drug, 21 reported headaches. In a control group of 1746 subjects given a placebo, 20 reported headaches. Denoting the proportion of headaches in the treatment group by pt and denoting the proportion of headaches in the control (placebo) group by PC, the relative risk is pt/pc.

The relative risk is a measure of the strength of the effect of the drug treatment. Another such measure is the odds ratio, which is the ratio of the odds in favor of a headache for the treatment group to the odds in favor of a headache for the control (placebo) group, found by evaluating

pt/1ptpc/1pc.

The relative risk and odds ratios are commonly used in medicine and epidemiological studies. Find the relative risk and odds ratio for the headache data. What do the results suggest about the risk of a headache from the drug treatment?

Find the relative risk for the headache data.

The relative risk=

(Round to three decimal places as needed.)

Find the odds ratio for the headache data.

The odds ratio=

(Round to three decimal places as needed.)

What do the results suggest about the risk of a headache from the drug treatment?

A.The drug has no risk because the relative risk and odds ratio are almost equal.

B.The drug appears to pose a risk of headaches because pt is greater than pc.

C.The drug appears to pose a risk of headaches because the odds ratio is greater than 1.0.

D.The drug does not appear to pose a risk of headaches because pt is slightly less than

pc.

7)In an experiment, college students were given either four quarters or a $1 bill and they could either keep the money or spend it on gum. The results are summarized in the table. Complete parts (a) through (c) below.

	Purchased Gum	Kept the Money
Students Given Four Quarters	26	14
Students Given a $1 Bill	19	29

a. Find the probability of randomly selecting a student who spent the money, given that the student was given four quarters.

The probability is (Round to three decimal places as needed.)

b. Find the probability of randomly selecting a student who kept the money, given that the student was given four quarters.

The probability is (Round to three decimal places as needed.)

c. What do the preceding results suggest?

A. A student given four quarters is more likely to have spent the money.

B. A student given four quarters is more likely to have kept the money.

C. A student given four quarters is more likely to have kept the money than a student given a $1 bill.

D. A student given four quarters is more likely to have spent the money than a student given a $1 bill.

8) The normal quantile plot shown to the right represents duration times (in seconds) of eruptions of a certain geyser from the accompanying data set. Examine the normal quantile plot and determine whether it depicts sample data from a population with a normal distribution.