All cannabinoid receptors are in the central nervous system

From the late 1970s to the early 1990s, adolescent substance use generally

a. increased. b. declined. c. stayed about the same. d. increased in terms of marijuana use, but declined in terms of alcohol use.

A survey reports how many high school students say they were "physically abused.". Before we decide how seriously to take these results, which questions do we need to have answered?

a. What were they told to include as examples of physical abuse? b. How many of them fought back after being physically abused? c. How many of them were seniors, juniors, and sophomores? d. Was this a double-blind study?