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  #1  
Old 03-05-2013
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Default Biostats ques

A clinical trial was conducted to evaluate the effect of metoprolol, a selective beta blocker, on overall and cardiovascular mortallities in patients with chronic heart failure. The patients with chronic heart failure were randomly assigned to receive metoprolol or placebo, and were followed for a period of 3 years. The purpose of RANDOMIZATION is to control?

A. Confounding
B. Selection bias
C. Observer's bias
D. Ascertainment bias
E. Effect modification

Hope to get little explanation with question
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Old 03-05-2013
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the purspose is to remove the bias(confounding bias)
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Old 03-05-2013
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A. Confounding
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Old 03-05-2013
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IMO, the answer is B
Randomization is to ensure the two group (treatment and control) has the same characteristic as such any effect seen will be attributable to the treatment only.

Quote:
Originally Posted by koolkiller88 View Post
A clinical trial was conducted to evaluate the effect of metoprolol, a selective beta blocker, on overall and cardiovascular mortallities in patients with chronic heart failure. The patients with chronic heart failure were randomly assigned to receive metoprolol or placebo, and were followed for a period of 3 years. The purpose of RANDOMIZATION is to control?

A. Confounding
B. Selection bias
C. Observer's bias
D. Ascertainment bias
E. Effect modification

Hope to get little explanation with question
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  #5  
Old 03-05-2013
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In the statistical theory of design of experiments, randomization involves randomly allocating the experimental units across the treatment groups. For example, if an experiment compares a new drug against a standard drug, then the patients should be allocated to either the new drug or to the standard drug control using randomization. Randomization reduces confounding by equalising so-called factors ( independent variables) that have not been accounted for in the experimental design.
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Last edited by Novobiocin; 03-05-2013 at 06:14 PM.
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  #6  
Old 03-05-2013
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oops.. sorry. I mistype the option. What I meant is confounding. A
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