INVESTIGATING STATISTICAL CONCEPTS, APPLICATIONS, AND METHODS

BRIEF SOLUTIONS TO INVESTIGATIONS

CHAPTER 1

Investigation 1.2.1: Smoking and Lung Cancer

(a) males

(b) EV = amount of smoking (categorical); RV = whether have lung cancer (categorical)

(c)

(d) 14/90 = .156; 8/114 = .070; ratio = 2.217

(e) (14´114)/(8´90)

(f) (213´114)/(8´278)=10.92

(g) (122´114)/(8´60)=28.98, the odds of lung cancer are almost 30 times higher for the chain smokers compared to the non-smokers

(h) The odds of lung cancer are 12.77 times higher for the smokers compared to the non-smokers

(i) Yes, as the amount of smoking increases so does the odds ratio (compared to non-smokers)

(j) There could be something else different about those who choose to smoke, e.g., diet, exercise

(k) Older people are more likely to smoker (before all the negative publicity) and to have cancer (just by being around longer!)

(l) No, the researchers forced the amounts of patients with and without lung cancer to be similar instead of seeing how often these outcomes occurred “naturally.”

(m) No, can always be other explanations (e.g., diet, exercise)

(n) Not clear how representative these patients were…

Investigation 1.2.2: Lung Cancer and Smoking (cont.)

(a) EV = smoking; RV = lung cancer death or not.

(b) Cohort study since identified and followed the explanatory variable groups and observed the resulting response.

(c) .005 - .00047 = .0046, a very small difference

(d) RR = (.005/.00047) = 10.64, OR = 10.77 (will be some rounding differences)

(e) Don’t have to rely on memory, can see how health changes over time, all patients are healthy to begin with

(f) Same as before, could be other differences about those who smoke

(g) Yes