Question

Reserve Problems Chapter 12 Section 1 Problem 11 An article in Technometrics (1974, Vol. 16, PP. 523-531) considered the following stack-loss data from a plant oxidizing ammonia to nitric add. Twenty-one daily responses of stack lass (the amount of ammonia escaping) were measured with air flow Xl, temperature.X1, and acid concentration 41 . 42 80 80 89 90 75 87 37 28 18 19 19 20 87 27 27 25 24 22 23 24 24 23 62 62 62 62 58 58 15 18 SA 18 17 11 14 13 11 12 8 87 93 93 87 80 89 88 82 93 89 86 72 79 80 10 19 18 59 50 58 50 SO 50 50 50 56 7 19 19 & 19 9 20 15 20 82 91 15 70 20 (e) Fit a linear regression model relating the results of the stack loss to the three regressor variables. Round your answers to two decimal places (e.g. 98.75) H+ xit (b) Estimate or Round your answer to two decimal places (e.g. 98.76). (c) Use the model in part (a) ta predict stack loss when xy = 59, 43 = 27. and x = 85. Round your answer to one decimal place (e.g. 98.7).

Answer 1

SUMMARY OUTPUT
Regression Statistics
Multiple R	0.95329
R Square	0.908762
Adjusted R Square	0.892661
Standard Error	3.332495
Observations	21
ANOVA
	df	SS	MS	F	Significance F
Regression	3	1880.444	626.8147	56.4417	4.77E-09
Residual	17	188.7939	11.10553
Total	20	2069.238
	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%
Intercept	-50.3149	6.577439	-7.64963	6.68E-07	-64.1921	-36.4378
x1	0.671232	0.130549	5.141619	8.16E-05	0.395798	0.946666
x2	1.296129	0.384436	3.371507	0.003624	0.48504	2.107218
x3	-0.00078	0.069219	-0.01122	0.991179	-0.14682	0.145262

Model is significant but x3 is not as p-value for all is < 0.05 except X3

1. Now, equation:

y = -50.3149 + 0.6712X1 + 1.296 X2 - 0.00078X3

2. Standard deviation : Standard error = 3.332495

Variance = MSE = 11.10553

3. X1 = 59,X2= 27, X3 = 85

y = -50.3149 + 0.6712 * 59 + 1.296 * 27 - 0.00078 * 85 = 24.2116

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