Using a sample of 200 students and the following model, we want to analyse the effect of class size on the students' academic success

 Using a sample of 200 students and the following model, we want to analyse the effect of class size on the students' academic success. Y = Bo + B.X + 44, The academic success variable (Y) is measured using a test score ranging from 0 (i.e. the poorest score) to 100 (highest score) and the class size (Xi) variable is a dummy variable equal to 1 for classes with more than 15 students and 0 otherwise. We obtain the following estimation output: Parameter Estimate Standard error Bo 75 10 B. -5.8 2 (a) Provide an interpretation for the parameters Bo and Bi. Are the signs of these coefficients in line with your expectations? [Maximum 100 words] (b) Calculate the 90 and 95 percent confidence intervals for B, and B.. [Maximum 200 words) (c) Is the estimated effect of class size on test scores statistically significant? Test this hypothesis at 5 percent significance level. [Maximum 200 words) (d) Suppose that the true model should also include a binary variable which is equal to 1 if families show high effort for their children's academic success and O if they show low effort. If this variable is negatively correlated with the class size, would omission of family effort variable lead to downward or upward bias for the estimate for B.? Show you calculations explicitly. [Maximum 300 words]