Question

would the variance of Z with respect to two independent variable, X and Y be subtracted to find the variance if Z = X-Y

Answer 1

No, to find the variance of Z when Z = X - Y, you would need to use the properties of variance. Since X and Y are independent variables, the variance of their sum or difference is equal to the sum of their variances. Therefore, you would subtract the variances of X and Y to find the variance of Z.