Refer to Exercise 15.22. a. Write a model for this experimental setting. b. Es...

Refer to Exercise 15.22.

a. Write a model for this experimental setting.

b. Estimate the parameters in the model.

c. Use the computer output shown here to conduct an analysis of variance. Use α = .05.

d. What conclusions can you draw concerning the best mixture from the four tested? (Note: The higher the response value, the better is the rocket propellant thrust.)

e. Compute the relative efficiency of the randomized block design relative to a completely randomized design. Interpret this value. Were the blocks effective in reducing the variability in experimental units? Explain.

REFERENCE:

15.22 : An experiment compares four different mixtures of the components oxidizer, binder, and fuel used in the manufacturing of rocket propellant. The four mixtures under test, corresponding to settings of the mixture proportions for oxide, are shown here.

To compare the four mixtures, five different samples of propellant are prepared from each mixture and readied for testing. Each of five investigators is randomly assigned one sample of each of the four mixtures and asked to measure the propellant thrust. These data are summarized next.

a. Identify the blocks and treatments for this experimental design.

b. Indicate the method of randomization.

c. Why would this design be preferable to a completely randomized design?