The accompanying MINITAB output resulted from a request to

Chapter 13, Problem 13.76

(choose chapter or problem)

The accompanying MINITAB output resulted from a request to fit the model Y 0 1x1 2x2 !. The regression equation is AREA 6.05 0.142 NAOH 0.0169 TIME Predictor Coef Stdev t-ratio p Constant 6.0483 0.5208 11.61 0.000 NAOH 0.14167 0.03301 4.29 0.005 TIME 0.016944 0.006601 2.57 0.043 s 0.4851 R-sq 80.7% R-sq (adj) 74.2% Analysis of Variance SOURCE DF SS MS F p Regression 2 5.8854 2.9427 12.51 0.007 Error 6 1.4118 0.2353 Total 8 7.2972 a. What proportion of observed variation in specific surface area can be explained by the model relationship? b. Does the chosen model appear to specify a useful relationship between the dependent variable and the predictors? c. Provided that % NaOH remains in the model, would you suggest that the predictor treatment time be eliminated? d. Calculate a 95% CI for the expected change in specific surface area associated with an increase of 1% in NaOH when treatment time is held fixed. e. MINITAB reported that the estimated standard deviation of 0 1(9) 2(60) is .162. Calculate a prediction interval for the value of specific surface area to be observed when % NaOH 9 and treatment time 60. 77.