The accompanying data resulted from an

Chapter 11, Problem 11.18

(choose chapter or problem)

The accompanying data resulted from an experiment to investigate whether yield from a certain chemical process depended either on the formulation of a particular input or on mixer speed. Speed 60 70 80 189.7 185.1 189.0 1 188.6 179.4 193.0 190.1 177.3 191.1 Formulation 165.1 161.7 163.3 2 165.9 159.8 166.6 167.6 161.6 170.3 A statistical computer package gave SS(Form) 2253.44, SS(Speed) 230.81, SS(Form*Speed) 18.58, and SSE 71.87. a. Does there appear to be interaction between the factors? b. Does yield appear to depend on either formulation or speed? c. Calculate estimates of the main effects. d. The fitted values are xijk i j ij, and the residuals are xijk xijk. Verify that the residuals are .23, .87, .63, 4.50, 1.20, 3.30, 2.03, 1.97, .07, 1.10, .30, 1.40, .67, 1.23, .57, 3.43, .13, and 3.57. e. Construct a normal probability plot from the residuals given in part (d). Do the ijks appear to be normally distributed? 19