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Consider the following annual model of the death rate (per million population) due to coronary heart disease in the U.S. (denoted by Y.): Y, =140+ 10.0C, +4.0E, -1.0M, +e, (2.5) (1.0) (0.5) N = 31 Standard errors are in parentheses where C = per capita cigarette consumption (pounds of tobacco) in year t Et = per capita consumption of edible saturated fats (pounds per butter, margarine) in year t M. = per capita consumption of meat (pounds) in year t a) Do the coefficient estimates in the regression above have the expected sign? I.e. do you expect Bc to be positive, BE to be positive, and By to be negative? Explain. b) Calculate the t-statistic for every coefficient estimate. Assume that the critical t-value for a two- sided test of statistical significance at the 5 percent level is 2.056. Is Ct, Et, or M, statistically significant? c) The most likely cause of a coefficient that is significant in the unexpected direction is omitted variable bias. Which of the variables listed below could possibly be an omitted variable that is causing PM's unexpected sign? (Hint: Use the table below for your answer). Corr (X1,X2) > 0 Corr (X1,X2) 0 Positive bias Negative bias Bomitted