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Old 10-11-2012
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Stats Comparing two patient groups

I can't get my head around the following question. Could someone answer and explain plz. Here it goes....

Two drugs, X and Y are being evaluated for treatment of CHF. Pts receiving drug X have cardiac index of 2.5 L/m2 (square) with 95% CI 1.5 to 3.5. Pts on drug Y have cardiac index of 1.7 L/m2 with 95% 0.7 to 2.7. A test of the significance of difference shows a p-value of 0.1. Which of the following is the likelihood that the difference in mean cardiac index of patients receiving drug X and drug Y is due to chance?

A) 0%
B) 2.5%
C) 5%
D) 7.5%
E) 10%
F) 66.7%
G) 95%

TBH, I don't even know WTH is it asking.....
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Old 10-11-2012
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E) 10 %, because p=0.1, which means there is a 10% probability that the difference between the 2 drugs is due to chance.
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Old 10-11-2012
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Quote:
Originally Posted by Teona View Post
E) 10 %, because p=0.1, which means there is a 10% probability that the difference between the 2 drugs is due to chance.
thanks for explanation....but i got a doubt..
here the 2 drugs 95%CI are overlapping---means there is no difference exist right? from kaplan videos.......
correct me ,i always get confused with these
thanks
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Quote:
Originally Posted by venky2600 View Post
thanks for explanation....but i got a doubt..
here the 2 drugs 95%CI are overlapping---means there is no difference exist right? from kaplan videos.......
correct me ,i always get confused with these
thanks
Yes, if the 2 confidence intervals overlap that means the groups are not significantly different in their outcomes. And p value states the same thing p>0.05, which means there is no difference.
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Originally Posted by Teona View Post
Yes, if the 2 confidence intervals overlap that means the groups are not significantly different in their outcomes. And p value states the same thing p>0.05, which means there is no difference.
thanks,

i thought 0% as answer..as no difference exist...
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Old 10-11-2012
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Quote:
Originally Posted by venky2600 View Post
thanks,

i thought 0% as answer..as no difference exist...
In my opinion, you could choose A) 0% when p value is< 0.05.

p<0.05 means that there is a statistical significance between the 2 drugs, which means that there is almost 0% chances that the statistical difference between the 2 is by chance.
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