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1. Consumer Reports provided extensive testing and ratings for more than 100 HDT

ID: 3054422 • Letter: 1

Question

1. Consumer Reports provided extensive testing and ratings for more than 100 HDTVs. An overall score, based primarily on picture quality, was developed for each model. In general, a higher overall score indicates better performance. The following data show the price and overall score for the ten 42-inch plasma televisions (The actual Consumer Report data changed here arbitrarily):

Brand

Price

Score

Dell

2800

60

Hisense

2800

55

Hitachi

2700

45

JVC

3500

50

LG

3300

55

Maxent

2000

38

Panasonic

4000

67

Phillips

3000

56

Proview

2500

32

Samsung

3000

40

Use the above data to develop and estimated regression equation and interpret the slope and intercept. Compute Coefficient of Determination and correlation coefficient and show their relation. Interpret the explanatory power of the model. Estimate the overall score for a 42-inch plasma television with a price of $3800. Finally, perform the test of significance for the slope coefficient. ?(Show work)

Brand

Price

Score

Dell

2800

60

Hisense

2800

55

Hitachi

2700

45

JVC

3500

50

LG

3300

55

Maxent

2000

38

Panasonic

4000

67

Phillips

3000

56

Proview

2500

32

Samsung

3000

40

Explanation / Answer

Regression equation is ,

Score = 8.8950+ 0.0138 Price

Slope = 0.0138 Slope is the change in the mean of distribution of Score by a unit change in Price.

Intercept =8.8950, this is the mean of the distribution of the Score when Price = 0

Coefficient of determination = 0.4908

Correlation coefficient = 0.701

The regression model can explain 49.08% variation in the dependent variable .

Estimate the overall score for a 42-inch plasma television ,

Score = 8.8950+ 0.0138 Price

price = 3800

Score = 8.8950+ 0.0138 *3800

Score = 55.82

test of significance for the slope coefficient,

pvalue(b1) = 0.024 < alpha = 0.05

Therefore reject H0.

SUMMARY OUTPUT Regression Statistics Multiple R 0.700603 R Square 0.490845 Adjusted R Square 0.4272 Standard Error 8.242984 Observations 10 ANOVA df SS MS F Significance F Regression 1 524.0257 524.0257 7.712294 0.024032 Residual 8 543.5743 67.94679 Total 9 1067.6 Coefficients Standard Error t Stat P-value Lower 95% Upper 95% Lower 95.0% Upper 95.0% Intercept 8.895044 14.95824 0.594658 0.568505 -25.5987 43.38881 -25.5987 43.38881 X Variable 1 0.013819 0.004976 2.777102 0.024032 0.002344 0.025294 0.002344 0.025294