Question: Elongation

Elongation of steel plate (Y) is related to the applied force in psi (X). Given the following data, perform a complete regression analysis and interpret your result.

x y

1.33 26

2.68 51

3.50 66

4.40 84

5.35 101

6.27 117

7.11 133

8.93 150

9.76 182

10.81 202

4a. Construct a scatter plot of this data. What does it suggest?

4b. Is there a useful linear relationship between Elongation and applied force? Justify your answer.

4c. What proportion of the observed variation in elongation can be explained by the model relationship?

4d. Predict elongation when applied force is 6.27, and compute the value of the corresponding residual.

4e. At x = 6 obtain a point estimate and 95% Confidence interval of the mean elongation.

Repeat at x = 12.

4f. At x = 6, obtain a point estimate and 95% confidence prediction interval for a single future value of elongation.