Question

1. A research study randomly assigned participants into two groups. One group was given Vitamin E to take daily. The other group received only a placebo pill. The research study followed the participants for eight years. After the eight years, the proportion of each group that developed a particular type of cancer was compared. What is the primary reason that the study used random assignment? a. To ensure that the groups are similar in all respects except for the level of Vitamin E. b. To ensure that a person does not know whether or not he/she is getting the placebo. c. To ensure that the study participants are representative of the larger population. O d. To eliminate bias in the study.

Answer 1

1)

O d. To eliminate bias in the study.

2)

Valid, because the sample size is large enough to represent the population.

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