QUESTION 40 Consider the following summary statistics of the variables x, y and z var(x) = 2.4, var(y)=3.2, var(z) =1.1 cov(x,y) = 3.1, cov(X,z) = 4.2, cov(y,z) = 8 What is the instrumental variable (IV) estimator of the effect of x on y when you use the variable z as an instrumental variable