Can you help me with this question, the symbols are confusing.

2. Let X1, X2, ..., Xn be iid pois(A) random variables. Recall E(X,) = A and Var(X;) = A. Consider three estimators of 1: M1 = Xi + 2, 12 = Xit2Xatax As = 2X - X1 (a) Calculate the expected value of each estimator. Which estimators are biased and which are unbiased? (6 points) (b) Calculate the variance of each estimator. (6 points) (c) Give the Mean Square Error of each estimator. Recall: MSE(0) can be written as {E(0) - 0}2 + Var(0). (6 points)