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two studies were conducted in the same population to assess the relationship between OCP use and risk of DVT.Study A showed increased risk of DVT among OCP users with a relative risk of 2 and 95% confidence interval of 1.2-2.8.Study B showed the following results,relative risk of 2.3 nd 95 % confidence interval of 0.8-3.1.which of the following statements is most true about these studies:

a.the result in study A is not statistically significant
b.the result in study B is biased
c.the result in study A is not accurate
d.the sample size in study B is small
e.P value in study B is less than 0.05

EEE

Ans : D

CI of study A is tighter than that of study B==> more precise study A ==>sample size in study A is big.
study B CI is wider ==> less precise===>small sample size.

Karim is right

d is rt,but why B cant be the ans,can somone explain,thnx