3. There are two variables, x and y. If the sample covariance between x and y is 120, the sample variance of x is 225, and the sample variance of y is 100 while the sample mean of y is 100 and the sample mean of x is 120 from a sample of 25 observations. (1 point each) 1) Calculate the estimated intercept of the simple regression model. 2) Calculate the slope coefficient of x if we run a simple regression model, y = bo + bx + ei 3) Calculate the R of the regression model and explain the meaning. 4) Show how to calculate the estimated slope coefficient (b1) confidence interval. Explain the meaning of the interval.