I always have trouble trying to do proofs. can you help me?
1. given mean is ui and variance sigma squared. indep obs.
prove that
(Ybar1-Ybar2-zz(alpha/2)*sigma*square root of 1/n1+1/n2),Ybar1-Ybar2+.....)
is a 100(1-alpha)% confidence interval for mu1-mu2
2. prove that (given Yij is a normal dist with mean ui and variance sigma squared)
s^2p=((n1-1)s1^2+(n2-1)s2^2)/n1+n2-2
3.prove that
((n1+n2-2)sp^2)/sigma aquared is a chi squared distn with n1+n2-2 degrees of freedom
please help me!!!! i have no idea!!!!
cheers
is an unbiased estimator or sigma squared
1. given mean is ui and variance sigma squared. indep obs.
prove that
(Ybar1-Ybar2-zz(alpha/2)*sigma*square root of 1/n1+1/n2),Ybar1-Ybar2+.....)
is a 100(1-alpha)% confidence interval for mu1-mu2
2. prove that (given Yij is a normal dist with mean ui and variance sigma squared)
s^2p=((n1-1)s1^2+(n2-1)s2^2)/n1+n2-2
3.prove that
((n1+n2-2)sp^2)/sigma aquared is a chi squared distn with n1+n2-2 degrees of freedom
please help me!!!! i have no idea!!!!
cheers
is an unbiased estimator or sigma squared