A study of cell phones and the risk of brain cancer looked at a group of 469people who
Chapter 0, Problem 9.16(choose chapter or problem)
A study of cell phones and the risk of brain cancer looked at a group of 469people who have brain cancer. The investigators matched each cancer patientwith a person of the same sex, age, and race who did not have brain cancer, thenasked about use of cell phones. This is(a) an observational study.(b) an uncontrolled experiment.(c) a randomized comparative experiment.
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