a. Regress the following equation using OLS, (i) Grade=Bo+ BSTH+ BMIC +u (Denote the parameter estimates Bo, B1, and B2) interpret the parameter estimates, and determine if the parameter estimates are significant at a=0.05. b. Regress the following two equations using OLS: (ii) Grade=Bo+ BISTH+ v (iii) MIC=80+ 8,STH+e (denote the parameter estimates Band B) (denote the parameter estimates and ) Verify that B =B + B8 c. Is B the OLS slope estimate from (ii), an unbiased estimate of ? Demonstrate your answer. MIC Grade STH 75 62.5 87.5 6 55 75 90 97.5 9 62.5 5 87.5 92.5 55 90 8 92.5 60 70 656 65 746278an 226x9655 12 10 3526011421532754 5