Which of the following is an observational study? A.
Fifty people are chosen that read 3 or more books per week. Fifty others are asked to read 3 or more books per week. Both groups are given an intelligence test. The results are analyzed and recorded.
B.
One hundred people are asked to read a random book. The results are recorded and analyzed.
C.
Fifty people that read 3 or more books a week and fifty people that read less than 3 or more books per week are chosen and each group is given an intelligence test. The results are then analyzed and interpreted.
D.
One hundred people are chosen. Fifty people are asked to read 3 or more books per week and fifty people are asked to read less than this. An intelligence test is given to each group and the results are then analyzed and interpreted.