Question: For n = 6 data points, the following quantities have been calculated:

\(\sum{xy}\) = 400 \(\sum{x}\) = 40 \(\sum{y}\) = 76 \(\sum\limits_{{}}{{{x}^{2}}}\) = 346 \(\sum{{{y}^{2}}}\) = 1160

(a) Determine the least squares regression line.

(b) Determine the standard error of estimate.

(c) Construct the 95% confidence interval for the mean of y when x = 7.0.

(d) Construct the 95% confidence interval for the mean of y when x = 9.0.

(e) Compared the width of the confidence interval obtained in part (c) with that obtained in part (d). Which is wider and why?