In the article “An Ultracentrifuge Flour Absorption Method” (Cereal Chemistry [1978]:...

In the article “An Ultracentrifuge Flour Absorption Method” (Cereal Chemistry [1978]: 96– 101), the authors discussed the relationship between water absorption for wheat flour and various characteristics of the flour. The model y = α ₁ β₁x₁ + β ₂x₂ + e was used to relate y = absorption (%) to x₁= flour protein (%) and x₂ = starch damage (Farrand units). Minitab output based on n =28 observations is given. Use a significance level of .05 for all tests requested.

a. Does the model appear to be useful? Test the relevant hypotheses.

b. Calculate and interpret a 95% confidence interval for b2.

c. Conduct tests for each of the following pairs of hypotheses.

d. Based on the results of Part (c), would you conclude that both independent variables are important? Explain.

e. An estimate of the mean water absorption for wheat with 11.7% protein and a starch damage of 57 is desired. Compute a 90% confidence interval for

f. A single shipment of wheat is received. For this particular shipment, x₁ = 11.7 and x₂= 57. Predict the water absorption for this shipment (a single y value) using a 90% interval.