why is it desirable to have the explanatory variables spread

why is it desirable to have the explanatory variables spread out to test a hypothesis regarding P1 or construct confidence intervals about B1? Choose the correct answer below. A. So the mean ofb1 is larger. B. So the standard deviation ofb1 is larger. c. So the standard deviation ofb1 is smaller. D. So the mean ofb1 is smaller.

Solution

answer will be B so the standard deviation of b1 is larger