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A company that holds the DVD distribution rights to movies previously released o

ID: 3219788 • Letter: A

Question

A company that holds the DVD distribution rights to movies previously released only in theaters wants to estimate sales revenue of DVDs based on box office success. The box office gross (in $millions) for each of 22 movies in the year that they were released and the DVD revenue (in $millions) in the following year are shown in the accompanying table, along with the summary statistics. A linear regression was performed on this data, and the result is the linear regression equation Yi = 11.361 + 0.3737X.

Movie

Gross (X)

DVD Revenue (Y)

X^2

Y^2

XY

1

113.36

79.09

12850.4896

6255.2281

8965.6424

2

178.11

105.61

31723.1721

11153.4721

18810.1971

3

165.77

49.54

27479.6929

2454.2116

8212.2458

4

92.56

60.24

8567.3536

3628.8576

5575.8144

5

107.39

61.64

11532.6121

3799.4896

6619.5196

6

87.25

55.29

7612.5625

3056.9841

4824.0525

7

84.79

49.51

7189.3441

2451.2401

4197.9529

8

69.93

39.58

4890.2049

1566.5764

2767.8294

9

85.44

46.19

7299.9936

2133.5161

3946.4736

10

102.94

36.55

10596.6436

1335.9025

3762.457

11

33.19

30.43

1101.5761

925.9849

1009.9717

12

148.38

30.53

22016.6244

932.0809

4530.0414

13

58.96

26.85

3476.2816

720.9225

1583.076

14

49.84

28.75

2484.0256

826.5625

1432.9

15

58.95

25.71

3475.1025

661.0041

1515.6045

16

52.39

29.59

2744.7121

875.5681

1550.2201

17

78.92

40.91

6228.3664

1673.6281

3228.6172

18

42.45

29.44

1802.0025

866.7136

1249.728

19

41.08

16.77

1687.5664

281.2329

688.9116

20

35.49

18.82

1259.5401

354.1924

667.9218

21

44.08

23.02

1943.0464

529.9204

1014.7216

22

15.23

18.59

231.9529

345.5881

283.1257

Totals

1746.5

902.65

178192.866

46828.8767

86437.0243

a. Determine the coefficient of determination, r2, and interpret its meaning.

r2=

(Round to four decimal places as needed.)

Interpret the meaning of r2. Choose the correct answer below.

(Round to two decimal places as needed.)

The value of r2 indicates that ____% of the variation in ____ (DVD revenues OR box office gross) can be explained by the variation in ___(DVD revenues OR box office gross)

b. Determine the standard error of the estimate.

SYX =

(Round to four decimal places as needed.)

c. How useful do you think this regression model is for predicting DVD revenue?

A. It is not useful for predicting DVD revenue because the coefficient of determination is close to 0.

B. It is very useful for predicting DVD revenue because the coefficient of determination is very close to 1.

C. It is not useful for predicting DVD revenue because the coefficient of determination is close to 1.

D. It is somewhat useful for predicting DVD revenue because the coefficient of determination is closer to 1 than it is to 0.

d. Can you think of other variables that might explain the variation in DVD revenue? (multiple choice)

A. Another variable could be the time of year when the movie was released in theaters.

B. Another variable could be the amount of money spent on marketing the DVD release.

C. Another variable could be the time of year when the DVD was released.

D. Another variable could be the genre of movie.

E. Another variable could be the amount of money spent on marketing the theater release.

Movie

Gross (X)

DVD Revenue (Y)

X^2

Y^2

XY

1

113.36

79.09

12850.4896

6255.2281

8965.6424

2

178.11

105.61

31723.1721

11153.4721

18810.1971

3

165.77

49.54

27479.6929

2454.2116

8212.2458

4

92.56

60.24

8567.3536

3628.8576

5575.8144

5

107.39

61.64

11532.6121

3799.4896

6619.5196

6

87.25

55.29

7612.5625

3056.9841

4824.0525

7

84.79

49.51

7189.3441

2451.2401

4197.9529

8

69.93

39.58

4890.2049

1566.5764

2767.8294

9

85.44

46.19

7299.9936

2133.5161

3946.4736

10

102.94

36.55

10596.6436

1335.9025

3762.457

11

33.19

30.43

1101.5761

925.9849

1009.9717

12

148.38

30.53

22016.6244

932.0809

4530.0414

13

58.96

26.85

3476.2816

720.9225

1583.076

14

49.84

28.75

2484.0256

826.5625

1432.9

15

58.95

25.71

3475.1025

661.0041

1515.6045

16

52.39

29.59

2744.7121

875.5681

1550.2201

17

78.92

40.91

6228.3664

1673.6281

3228.6172

18

42.45

29.44

1802.0025

866.7136

1249.728

19

41.08

16.77

1687.5664

281.2329

688.9116

20

35.49

18.82

1259.5401

354.1924

667.9218

21

44.08

23.02

1943.0464

529.9204

1014.7216

22

15.23

18.59

231.9529

345.5881

283.1257

Totals

1746.5

902.65

178192.866

46828.8767

86437.0243

Explanation / Answer

From the formula for r2,

R2 is calculated as

r = sqrt(0.5640)= 0.75

The value of r2 indicates that _56.4___% of the variation in ____ DVD revenues can be explained by the variation in box office gross)

b)

C) The correct answer is D. It is somewhat useful for predicting DVD revenue because the coefficient of determination is closer to 1 than it is to 0.

D) A,B,C,D could be possible answers to this question.

0.5640
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