A simple linear regression on x1 and y yields R^2 of 0.2
A simple linear regression on x2 and y yields R^2 of 0.1
What is a upper and lower bound of R^2 if we do a multiple linear regression on x1, x2 and y?
My guess on the lower bound is 0.2 if x1 and x2 are perfectly correlated, but is the upper bound 0.3? Or little bit less than 0.3?