An article23 summarized results from the Nurses’ Health Study and the Health Professionals Follow-Up Study. The article reported (with RR = relative risk) that “Compared with nonregular use, regular...

An article23 summarized results from the Nurses’ Health Study and the Health Professionals Follow-Up Study. The article reported (with RR = relative risk) that “Compared with nonregular use, regular aspirin use was associated with lower risk of overall cancer (RR 0.97; 95% CI 0.94, 0.99), which was primarily due to a lower incidence of gastrointestinal cancers, especially colorectal cancers (RR 0.81; 95% CI 0.75, 0.88).”

a. Identify the response variables and the explanatory variable for these two results. Explain how to interpret the confidence interval about colorectal cancers.

b. Would the association with overall cancer be considered (i) significant or non-significant? (ii) strong or weak? Explain.