6. (10 Points) )Let X1, X2, ..., Xni be a random sample from a distribution with expected value uand known variance 62. Let Yb Y2, ..., Ynz be a randsom sample from a distribution with the same expected value p and known variance 5'\". X's and Y's are independent. After taking Econ 318 _ and attending all the lectures, you decide you will estimate u with i7: "f* (1 \" \"1 f \"\"1"\"- U 5 \" 3 1' Is your estimator for u biased or unbiased? Show your work