Please help with the following

Consider a simple random sample from random variables X1...,X, which have mean u = E( X; ) and variance o2 = var( X; ). Find: 1. E[ (Xi - M ) 2 ] 2. El Ci-1(Xi - M ) 2] 3. El T ER1 (X; - M ) 2 ] 4. E[ ( X - M )2 ] where X is the sample mean