The article “Physical Properties of Cumin Seed” (J. of Agric. Engr. Res., 1996: 93–98) c...

The article “Physical Properties of Cumin Seed” (J. of Agric. Engr. Res., 1996: 93–98) considered a quadratic regression of y = bulk density on x = moisture content. Data from a graph in the article follows, along with Minitab output from the quadratic fit.

a. Does a scatter plot of the data appear consistent with the quadratic regression model?

b. What proportion of observed variation in density can be attributed to the model relationship?

c. Calculate a 95% CI for true average density when moisture content is 13.7.

d. The last line of output is from a request for estimation and prediction information when moisture content is 14. Calculate a 99% PI for density when moisture content is 14.

e. Does the quadratic predictor appear to provide useful information? Test the appropriate hypotheses at significance level .05.