Confidence Intervals for the Slope of a Least Squares Regression Line

• If the random errors of the simple linear regression are normally distributed, then the sampling distribution of b is normal.

• To calculate the estimator of the standard deviation of b, s_b , the quantities of S_xx, S_xy , and S_yy will be needed.

• To estimate the slope of the regression line β, use the t-distribution with ν = n − 2 degrees of freedom.