A. Determine whether the given description corresponds to an observational study or an experiment. Give a brief explanation of your choice.
1. In a clinical trial of the cholesterol drug Lipitor, 188 subjects were given 20-mg doses of the drug, and 3.7% of them experienced nausea
B. identifies which of these types of sampling is used: random, systematic, convenience, stratified, or cluster.
1. Ecology: When collecting data from different sample location in a lake, a researcher uses the "line transect method" by stretching a rope across the lack and collecting samples interval of 5 meters.
2. Dictionary: The author collected sample data by randomly selected 20 different pages from printed version of the Merriam-Webster Dictionary and then counting the number of defined words in each of those pages.
3. Market Research: In order to test for a gender gap in the way that men and women purchase cars, the Grant Survey Company polls exactly 750 adult's men and 750 adult women randomly selected from adults in the United States.