"Moderate Walking Helps the Mind Stay Sharper" is the title of an article that reports, "Women who walked 1 1/2 hours per week had a 20% lower risk of mental impairment than those who walked less than 40 minutes per week, according to a study of 18,766 elderly women conducted by researchers from the Harvard School of Public Health."19
a. Was this an observational study or an experiment?
b. Which one of these would be most worrisome here: confounding variables, people's behaviors affected by their awareness of participating in a prospective study, or anecdotal evidence?
c. Suppose age was thought to be a possible confounding variable in the relationship between walking and mental fitness. How could researchers handle this problem?
d. Report the explanatory variable using a single word from the article's title _______ and identify its variable type:
1. Categorical
2. Quantitative
e. Report the response variable using two words from the article's explanation in quotations _______ and identify its variable type:
1. Categorical
2. Quantitative
f. Do we compare means or proportions?