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Develop a regression model using the manufacturing.xlsx file. Use Number of prod

ID: 3044920 • Letter: D

Question

Develop a regression model using the manufacturing.xlsx file. Use Number of production workers, Value Added by manufacturing, Value of industrial shipments, New capital expenditures, and End of year inventory to predict Cost of materials. The level of significance will be 0.05.

Set up and solve this problem in Excel. Use highlighting to emphasize important cells.

What proportion of the variance in the dependent variable is accounted for by the combined effect of the independent variables.

Does it appear that an appropriate number of variables are used? Explain.

   Were any variables that were included in the initial solution not significant? If yes, list them.

   Are there any outliers? If yes, list them.

What is the final regression equation?

Number of employees

Industrial group

Cost of Materials

End of year inventory

New capital expenditures

Value of industrial shipments

Number of production workers

52

3

4219

929

292

2

47

74

3

5357

1427

454

2

63

13

3

1061

325

20

1

12

17

3

707

267

84

1

13

169

3

10421

2083

534

3

147

51

3

4140

697

220

2

41

55

3

7125

1446

176

2

44

84

3

8994

1014

423

2

76

61

3

5504

1291

464

2

47

27

4

716

356

22

1

22

200

4

8926

2314

200

3

178

294

4

11121

2727

189

3

250

38

4

2283

682

29

1

32

17

4

364

197

21

1

14

34

4

1813

450

20

1

28

1

4

71

17

2

1

1

31

4

1321

526

16

1

25

224

4

12376

2747

465

3

179

83

5

9661

578

539

3

68

172

5

19285

3979

1071

4

147

257

5

18632

3329

711

4

209

51

5

2170

355

88

1

43

82

5

7290

580

182

2

68

94

5

8135

1604

715

2

78

273

6

12980

3535

481

3

233

70

6

4011

829

358

2

53

37

6

5101

447

128

2

29

81

6

3755

956

177

2

61

54

6

2694

718

109

2

39

15

7

3279

725

698

2

11

116

7

20596

4257

3143

4

90

55

7

10604

1502

2360

3

42

212

7

24634

3976

1352

4

163

232

7

28963

5427

1750

4

182

403

8

8483

894

1277

4

136

121

8

6940

1216

311

3

16

136

8

8863

3736

618

3

57

69

8

2823

874

144

2

25

604

8

29572

4300

2959

4

437

41

8

3811

688

198

2

28

21

8

1047

577

66

2

12

65

8

2055

504

130

2

50

Number of employees

Industrial group

Cost of Materials

End of year inventory

New capital expenditures

Value of industrial shipments

Number of production workers

52

3

4219

929

292

2

47

74

3

5357

1427

454

2

63

13

3

1061

325

20

1

12

17

3

707

267

84

1

13

169

3

10421

2083

534

3

147

51

3

4140

697

220

2

41

55

3

7125

1446

176

2

44

84

3

8994

1014

423

2

76

61

3

5504

1291

464

2

47

27

4

716

356

22

1

22

200

4

8926

2314

200

3

178

294

4

11121

2727

189

3

250

38

4

2283

682

29

1

32

17

4

364

197

21

1

14

34

4

1813

450

20

1

28

1

4

71

17

2

1

1

31

4

1321

526

16

1

25

224

4

12376

2747

465

3

179

83

5

9661

578

539

3

68

172

5

19285

3979

1071

4

147

257

5

18632

3329

711

4

209

51

5

2170

355

88

1

43

82

5

7290

580

182

2

68

94

5

8135

1604

715

2

78

273

6

12980

3535

481

3

233

70

6

4011

829

358

2

53

37

6

5101

447

128

2

29

81

6

3755

956

177

2

61

54

6

2694

718

109

2

39

15

7

3279

725

698

2

11

116

7

20596

4257

3143

4

90

55

7

10604

1502

2360

3

42

212

7

24634

3976

1352

4

163

232

7

28963

5427

1750

4

182

403

8

8483

894

1277

4

136

121

8

6940

1216

311

3

16

136

8

8863

3736

618

3

57

69

8

2823

874

144

2

25

604

8

29572

4300

2959

4

437

41

8

3811

688

198

2

28

21

8

1047

577

66

2

12

65

8

2055

504

130

2

50

Explanation / Answer

1. What proportion of the variance in the dependent variable is accounted for by the combined effect of the independent variables?

Solution:

The value of the coefficient of determination or R square is given as 0.9247, which means about 92.47% of the variance in the dependent variable cost of materials is accounted for by the combined effect of the independent variables.

2. Does it appear that an appropriate number of variables are used? Explain.

Solution:

Yes, it appears that an appropriate number of variables are used because multiple correlation coefficient value is given as 0.9616 which indicate that there is a strong relationship between dependent variable cost of materials and combined effect of independent variables.

3. Were any variables that were included in the initial solution not significant? If yes, list them.

Solution:

Yes, there is one variable ‘value added by manufacturing’ is not significant because p-value for this variable is given as 0.3759 which is greater than 5% level of significance.

4. Are there any outliers? If yes, list them.

Solution:

Yes, some variables included outliers. These variables are given as cost of materials, number of production workers, value added by manufacturing, and new capital expenditures.

5. What is the final regression equation?

Solution:

Final regression equation is given as below:

Cost of materials = -1830.068402 + 16.65776167* Number of production workers + 1426.644281* Value of industrial shipments + 2.390667027* New capital expenditures + 2.426873994* End of year inventory

First Regression

SUMMARY OUTPUT

Regression Statistics

Multiple R

0.961610238

R Square

0.924694251

Adjusted R Square

0.913284289

Standard Error

2242.431623

Observations

39

ANOVA

df

SS

MS

F

Significance F

Regression

5

2037616181

407523236.2

81.0427105

1.47823E-17

Residual

33

165940486.3

5028499.584

Total

38

2203556667

Coefficients

Standard Error

t Stat

P-value

Lower 95%

Upper 95%

Intercept

-2167.411939

1187.686116

-1.82490299

0.07707972

-4583.7775

248.95362

Number of production workers

19.0485025

6.880248761

2.768577585

0.00916395

5.050531213

33.04647378

Value Added by manufacturing

-0.078803362

0.087799646

-0.89753622

0.37593464

-0.25743308

0.099826359

Value of industrial shipments

1721.808578

770.7390016

2.233971

0.03237736

153.7282968

3289.888859

New capital expenditures

2.684434086

0.766074752

3.50414118

0.00134022

1.125843291

4.24302488

End of year inventory

2.380197705

0.503683044

4.725586322

4.1315E-05

1.355446851

3.404948558

Second regression after deleting insignificant variable

SUMMARY OUTPUT

Regression Statistics

Multiple R

0.960653914

R Square

0.922855943

Adjusted R Square

0.913780172

Standard Error

2236.010767

Observations

39

ANOVA

df

SS

MS

F

Significance F

Regression

4

2033565366

508391341.6

101.6834715

2.02563E-18

Residual

34

169991301.1

4999744.149

Total

38

2203556667

Coefficients

Standard Error

t Stat

P-value

Lower 95%

Upper 95%

Intercept

-1830.068402

1123.420054

-1.629015252

0.112541757

-4113.132625

452.9958216

Number of production workers

16.65776167

6.325547773

2.633410144

0.012628389

3.802702012

29.51282133

Value of industrial shipments

1426.644281

695.0616974

2.052543374

0.047878174

14.10897102

2839.179591

New capital expenditures

2.390667027

0.690651369

3.461467154

0.001468254

0.987094583

3.794239471

End of year inventory

2.426873994

0.499556606

4.858056056

2.62207E-05

1.41165283

3.442095157

Cost of materials = -1830.068402 + 16.65776167* Number of production workers + 1426.644281* Value of industrial shipments + 2.390667027* New capital expenditures + 2.426873994* End of year inventory

SUMMARY OUTPUT

Regression Statistics

Multiple R

0.961610238

R Square

0.924694251

Adjusted R Square

0.913284289

Standard Error

2242.431623

Observations

39

ANOVA

df

SS

MS

F

Significance F

Regression

5

2037616181

407523236.2

81.0427105

1.47823E-17

Residual

33

165940486.3

5028499.584

Total

38

2203556667

Coefficients

Standard Error

t Stat

P-value

Lower 95%

Upper 95%

Intercept

-2167.411939

1187.686116

-1.82490299

0.07707972

-4583.7775

248.95362

Number of production workers

19.0485025

6.880248761

2.768577585

0.00916395

5.050531213

33.04647378

Value Added by manufacturing

-0.078803362

0.087799646

-0.89753622

0.37593464

-0.25743308

0.099826359

Value of industrial shipments

1721.808578

770.7390016

2.233971

0.03237736

153.7282968

3289.888859

New capital expenditures

2.684434086

0.766074752

3.50414118

0.00134022

1.125843291

4.24302488

End of year inventory

2.380197705

0.503683044

4.725586322

4.1315E-05

1.355446851

3.404948558