Re: Sample Questions of ISI ME I (Mathematics) 2010 Discussion

Posted by Dreyfus on Jun 21, 2014; 5:43am
URL: http://discussion-forum.276.s1.nabble.com/Sample-Questions-of-ISI-ME-I-Mathematics-2010-Discussion-tp4850019p7593244.html

@soumen...actually u r not applying the var formula correctly
Var(mean of Xs) =( 1/n²)( varx1 + varx2 + varx3+........varxn+ sum of all covariance terms)
Sum of all covariance pair is equal to n(n-1)*p as all cov b/w diff pairs of x's are same.
And sum of variances is equal to n*sigma²
So Var (mean of Xs) = (1/n²)*(n*sigma² + n(n-1)*p)