Consider a simple regression in which the dependent variable mim ¼ mean income of males who are 18 years of age or older, in thousands of dollars. the explanatory variable pmhs ¼ percent of males 18 or older who are high school graduates. the data consist of 51 observations on the 50 states plus the district of columbia. thus mim andpmhs are ‘‘state averages.’’ the estimated regression, along with standard errors and t-statistics, is