Suppose that x and y are two variables of a population and that the assumptions for regression inferences are met with x as the predictor variable and y as the response variable.

a. What statistic is used to estimate the slope of the population regression line?

b. What statistic is used to estimate the y-intercept of the population regression line?

c. What statistic is used to estimate the common conditional standard deviation of the response variable corresponding to fixed values of the predictor variable?