Question

In a simple linear regression based on 28 observations, the following information is provided:

yˆ= −6.99 + 1.15x and s_e = 2.40. Also, se(y^0) evaluated at x = 28 is 1.46.

[You may find it useful to reference the t table.]

a. Construct the 95% confidence interval for E(y) if x = 28. (Round intermediate calculations to at least 4 decimal places, "t_α/2,df" value to 3 decimal places, and final answers to 2 decimal places.)

Confidence interval:

b. Construct the 95% prediction interval for y if x = 28. (Round intermediate calculations to at least 4 decimal places, "t_α/2,df" value to 3 decimal places, and final answers to 2 decimal places.)

Prediction interval:

c. Which interval is narrower?

• Prediction interval, since it does not include the variability caused by the error term.

• Prediction interval, since it includes the variability caused by the error term.

• Confidence interval, since it does not include the variability caused by the error term.

• Confidence interval, since it includes the variability caused by the error term.

Answer 1