The manufacturer of a new vitamin (vitamin x) decides to sponsor a study to determine the vitamin’s effectiveness in curing the common cold. five hundred college students having a cold were recruited from colleges in the san diego area and were paid to participate as subjects in this study. the subjects were each given two tablets of vitamin x a day. based on information provided by the subjects themselves, 457 of the 500 subjects were cured of their colds within 3 days. (the average number of days a cold lasts is 4.87 days.) as a result of this study, the manufacturer launched an advertising campaign based on the claim that “vitamin x is more than 90% effective in curing the common cold.”
a: describe as specifically as you can the target population for the study
b: describe the sampling frame for the study
c: was the study a controlled study? explain
d: list four possible causes other than the effectiveness of vitamin c itself that could have confounded the results of the study