The formula for the standard error of the sample slope b is se = s/∑(x - )2, where s is the residual standard deviation of y.
a. Show that the smaller the value of s, the more precisely b estimates β.
b. Explain why a small s occurs when the data points show little variability about the prediction equation.
c. Explain why the standard error of b decreases as the sample size increases and when the x values display more variability.