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{Exercise 15.28} Use computer software packages, such as Minitab or Excel, to so

ID: 3394595 • Letter: #

Question

{Exercise 15.28}

Use computer software packages, such as Minitab or Excel, to solve this problem.

Consider the following data for a dependent variable y and two independent variables, x1 and x2.


The estimated regression equation for this data is

= -22.4+ 1.99x1 + 4.92x2

Round your answers to two decimal places.

a. Develop a 95% confidence interval for the mean value of y when x1 = 45 and x2 = 15.

95% confidence interval is _________________ to _________________ .

b. Develop a 95% prediction interval for y when x1 = 45 and x2 = 15.

95% prediction interval is _________________ to _________________ .

x1 x2 y 30 12 95 47 11 109 24 17 113 51 17 178 41 6 94 52 20 175 75 7 170 36 13 117 60 13 142 76 16 211

Explanation / Answer

From excel, we get the following output -

SUMMARY OUTPUT Regression Statistics Multiple R 0.96517519 R Square 0.93156315 Adjusted R Square 0.91200976 Standard Error 12.0987836 Observations 10 ANOVA df SS MS F Significance F Regression 2 13947.73604 6973.868 47.64203 8.38523E-05 Residual 7 1024.663961 146.3806 Total 9 14972.4 Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Lower 95.0% Upper 95.0% Intercept -22.393849 17.70685058 -1.2647 0.246455 -64.26389772 19.4762 -64.2639 19.4762 x1 1.98798431 0.231291334 8.595153 5.75E-05 1.441067209 2.534901 1.441067 2.534901 x2 4.9231077 0.906956759 5.428161 0.000979 2.778495749 7.06772 2.778496 7.06772