two samples: X_1,,,,,,,,,,,,,,,,X_15 and Y_1,,,,,,,Y_15 and i need to find two sided hypothesis . Assuming normally dist, furthermore, I know how to get \frac{n(n+m+1)}{2}i.e e(variable) and \frac{n*m(+1)}{12} ie var
So I got, pivotal qty \frac{\over{X}-\mu}{\frac{\sigma}{\sqrt{n}}} and C.I E(S_n)\frac{\pm z_0.025*var(S_n)}{\sqrt{n+m} If any one could see my logic of thinking and help me from here please