A study claims that the combination of vitamin C with vitamin E is more effectiv
ID: 3328528 • Letter: A
Question
A study claims that the combination of vitamin C with vitamin E is more effective for preventing the flu than vitamin C alone. In the study, a group of researchers studied 1132 subjects. The subjects were randomly assigned to one of the three study groups. The first group of 310 subjects were instructed to take 600 mg daily of vitamin C. The second group of 418 subjects were instructed to take 600 mg of vitamin C and 200 IU of vitamin E daily. The third group of 404 subjects were instructed to take 600 mg of vitamin C and 400 IU of vitamin E daily. The incidence of flu over a season was recorded. All subjects knew which treatment they were receiving. i) In this study, which group is the control group? Blank 1 A) Group 2 B) the 1132 subjects C) Group 3 D) Group 1 E) There is no control group. ii) The study is Blank 2 A) double-blind B) not an experiment C) not blind D) blind, but not double-blind E) none of the above
Explanation / Answer
i) D) Group 1
Because, a control group is one which does not get treated or treated normally and used to be compared with the results of the treatment of research groups and thus control group acts as a bench mark. In this experiment, first group is taking vitamin C only, so it is said to be a control group. The reason is as follows:
We are comparing the effect of vitamin C alone on the flu which is the normal case by giving 1st group only C vitamin and the combination of vitamins C and E on the flu on treating research groups. For all the three groups we are giving the same quantity of vitamin C for correct comparison.
ii) C) not blind
The study is not blind because the subjects or the participants knew what they were receiving. If the participants doesn't know about what they were receiving, the study is said to be blind.
It is not double blind because the study is known as double blind only when both the participants and the researchers do not know what the participants are receiving but here the participants know what they are receiving. Thus, option A) is incorrect.
When it is proved to be not blind, we cannot say "it is blind but not double blind" and the study here is not blind and not double blind. Thus,option D) is incorrect.
And the given study is an experiment as it satisfied the experiment conditions of independent variables, testing by researchers and other criteria. Thus, B) is incorrect.
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