LibraryPirate

REVIEW QUESTIONS AND EXERCISES 671
cocaine, amphetamines, hallucinogens, or some other nonopioid besides marijuana (D). In ethnic
group II the abused drug category and the numbers involved were as follows:
A1282 B1322 C1132 D1the remainder2
Can one conclude from these data that there is a relationship between ethnic group and choice of
drug to abuse Let a = .05 and find the p value.
29. Solar keratoses are skin lesions commonly found on the scalp, face, backs of hands, forearms, ears,
scalp, and neck. They are caused by long-term sun exposure, but they are not skin cancers. Chen
et al. (A-27) studied 39 subjects randomly assigned (with a 3 to 1 ratio) to imiquimod cream and
a control cream. The criterion for effectiveness was having 75 percent or more of the lesion area
cleared after 14 weeks of treatment. There were 21 successes among 29 imiquimod-treated subjects
and three successes among 10 subjects using the control cream. The researchers used Fisher’s exact
test and obtained a p value of .027. What are the variables involved Are the variables quantitative
or qualitative What null and alternative hypotheses are appropriate What are your conclusions
30. Janardhan et al. (A-28) examined 125 patients who underwent surgical or endovascular treatment
for intracranial aneurysms. At 30 days postprocedure, 17 subjects experienced transient/persistent
neurological deficits. The researchers performed logistic regression and found that the 95 percent
confidence interval for the odds ratio for aneurysm size was .09–.96. Aneurysm size was
dichotomized as less than 13 mm and greater than or equal to 13 mm. The larger tumors indicated
higher odds of deficits. Describe the variables as to whether they are continuous, discrete, quantitative,
or qualitative. What conclusions may be drawn from the given information
31. In a study of smoking cessation by Gold et al. (A-29), 189 subjects self-selected into three treatments:
nicotine patch only (NTP), Bupropion SR only (B), and nicotine patch with Bupropion SR
1NTP + B2. Subjects were grouped by age into younger than 50 years old, between 50 and 64,
and 65 and older. There were 15 subjects younger than 50 years old who chose NTP, 26 who chose
B, and 16 who chose NTP + B. In the 50–64 years category, six chose NTP, 54 chose B, and 40
chose NTP + B. In the oldest age category, six chose NTP, 21 chose B, and five chose NTP + B.
What statistical technique studied in this chapter would be appropriate for analyzing these data
Describe the variables involved as to whether they are continuous, discrete, quantitative, or qualitative.
What null and alternative hypotheses are appropriate If you think you have sufficient information,
conduct a complete hypothesis test. What are your conclusions
32. Kozinszky and Bártai (A-30) examined contraceptive use by teenage girls requesting abortion in
Szeged, Hungary. Subjects were classified as younger than 20 years old or 20 years old or older. Of
the younger than 20-year-old women, 146 requested an abortion. Of the older group, 1054 requested
an abortion. A control group consisted of visitors to the family planning center who did not request
an abortion or persons accompanying women who requested an abortion. In the control group, there
were 147 women under 20 years of age and 1053 who were 20 years or older. One of the outcome
variables of interest was knowledge of emergency contraception. The researchers report that, “Emergency
contraception was significantly [(Mantel–Haenszel) p 6 .001] less well known among the
would-be aborter teenagers as compared to the older women requesting artificial abortion
1OR = .072 than the relevant knowledge of the teenage controls 1OR = .102.” Explain the meaning
of the reported statistics. What are your conclusions based on the given information
33. The goal of a study by Crosignani et al. (A-31) was to assess the effect of road traffic exhaust
on the risk of childhood leukemia. They studied 120 children in Northern Italy identified through
a population-based cancer registry (cases). Four controls per case, matched by age and gender,