Question

Fitting the simple linear regression model to the n= 27 observations on x = modulus of elasticity and y = flexural strength given in Exercise 15 of Section 12.2 resulted in yˆ = 7.592, sYˆ = .179 when x = 40 and yˆ = 9.741, sYˆ = .253 for x = 60.
a. Explain why sY ˆ is larger when x = 60 than when x = 40.
b. Calculate a confidence interval with a confidence level of 95% for the true average strength of all beams whose modulus of elasticity is 40.
c. Calculate a prediction interval with a prediction level of 95% for the strength of a single beam whose modulus of elasticity is 40.

Answer 1

Answer: ---- Date: ---7/7/2019