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The following partial MINITAB regression output for the Fresh detergent data rel

ID: 3233584 • Letter: T

Question

The following partial MINITAB regression output for the Fresh detergent data relates to predicting demand for future sales periods in which the price difference will be .10


(a) Report a point estimate of and a 95 percent confidence interval for the mean demand for Fresh in all sales periods when the price difference is .10. (Round your answers to 3 decimal places.)

(b) Report a point prediction of and a 95 percent prediction interval for the actual demand for Fresh in an individual sales period when the price difference is .10. (Round your answers to 3 decimal places.)


dv   =   


(d) For this case: n = 30, b0 = 8.413689, b1 = -.299329, and s = .663218. Using this information, and your result from part (c), find 99 percent confidence and prediction intervals for mean and individual demands when x = .10. (Round your answers to 4 decimal places.)

Predicted Values for New Observations New Obs Fit SE Fit 95% CI 95% PI 1 8.3838 .1540 (8.0682, 8.6993) (6.9891, 9.7785) 2 8.3389 .121 (8.0903, 8.5874) (6.9578, 9.7200)

Explanation / Answer

Part-a

Point estimate==(8.6993+8.0682)/2= 8.38375

Confidence interval= (8.0682, 8.6993)

Part-b

Point estimate==(8.6993+8.0682)/2= 8.38375

Confidence interval= (6.9891, 9.7785)

Part-c

We have syhat=0.1540 and s=0.663218 so that

Distance =(0.1540/0.663218)2=0.053917386

Part-d

Critical t=t0.01/2(n-2)=2.763

So, 99% CI=8.38375±2.763*sqrt(1/30+0.053917386)=( 7.5676    9.1999)

And, 99% PI=8.38375±2.763*sqrt(1+1/30+0.053917386)=( 5.5027              11.2648)