True, or false? a. In 2 2 tables, statistical independence is equivalent to a population odds ratio value of = 1.0. b. We

True, or false?

a. In 2 × 2 tables, statistical independence is equivalent to a population odds ratio value of θ = 1.0.

b. We found that a 95% confidence interval for the odds ratio relating having a heart attack (yes, no) to drug (placebo, aspirin) is (1.44, 2.33). If we had formed the table with aspirin in the first row (instead of placebo), then the 95% confidence intervalwould have been (1/2.33, 1/1.44) = (0.43, 0.69).

c. Using a survey of college students, we study the association between opinion about whether it should be legal to (1) use marijuana, (2) drink alcohol if you are 18 years old.We may get a different value for the odds ratio if we treat opinion about marijuana use as the response variable than if we treat alcohol use as the response variable.

d. Interchanging two rows or interchanging two columns in a contingency table has no effect on the value of the X2 orG2 chi-squared statistics. Thus, these tests treat both the rows and the columns of the contingency table as nominal scale, and if either or both variables are ordinal, the test ignores that information.

e. Suppose that income (high, low) and gender are conditionally independent, given type of job (secretarial, construction, service, professional, etc.).

Then, income and gender are also independent in the 2 × 2 marginal table

(i.e., ignoring, rather than controlling, type of job).