homework using EVIEWS (FOR ANYONE WHO CAN USE EVIEWS)

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a_5_s-15_revised_answers.doc

YOURLASTNAME, YourFirstName

Assignment 5 - REVISED

Save this document as A5-YourLastNameFirstName.doc. Type or copy and paste your responses to the instructions and questions into this document following each instruction or question.

1. You want to estimate a model for the demand for electricity by households in the U.S. States of the following form: Quantity of electricity consumed= f (Price of electricity, Price of gas, Income, Housing).

FOR THE REVISION YOU SHOULD USE QELEC/HOUSING AS THE DEPENDENT VARIABLE AND INCOME/HOUSING AS THE INDEPENDENT VARIABLE AND OMIT HOUSING AS AN INDEPENDENT VARIABLE. COMPARE THE RESULTS OF THIS REVISION WITH YOUR ORIGINAL RESULTS.

Obtain the most up-to-date data for sales of electricity, the residential price of electricity and the price of natural gas from the website of the U.S. Energy Information Administration ( http://www.eia.gov/electricity/ and http://www.eia.gov/naturalgas/ ) . Obtain data on the number of housing units from the U.S. Bureau of the Census http://www.census.gov/popest/data/housing/totals/2012/index.html )

and personal Income from the U.S. Bureau of Economic Analysis ( http://www.bea.gov/regional/index.htm )

Add each series to an EViews workfile and change the names to QELEC, PELEC, PGAS, INCOME and HOUSING:

a. Carefully identify the series including providing the url for the data.

b. Tell why you think the data series is or is not exactly what you should use in your estimation.

c. Paste the variable names for each series and only the first and the last observations into your assignment.

The Excel file Assignment 5 data contains all the identifying information for the data I used. You mayhave found some slightly different data.

STATE

QELEC

PELEC

PGAS

INCOME

HOUSING

1

Alabama

3256.000

10.99000

12.54000

181816.0

2189545.

51

Wyoming

313.0000

10.28000

8.540000

32018.00

265162.0

2. Type the equation you will estimate and explain it including your theory and the expected signs for each estimated coefficient.

Theory of demand QELEC = C(1)*PELEC + C(2)*PGAS + C(3)*INCOME +C(4)HOUSING + C(5)

C(1) –

C(2) +

C(3) +

C(4)+

C(5) no expectation

Dependent Variable: QELEC

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

PELEC

-94.46757

53.30388

-1.772246

0.0831

PGAS

39.22659

51.56934

0.760657

0.4508

INCOME

-0.008121

0.003297

-2.463220

0.0177

HOUSING

0.001853

0.000400

4.628823

0.0000

C

994.6281

356.9909

2.786144

0.0078

R-squared

0.876198

    Mean dependent var

2726.780

Adjusted R-squared

0.865193

    S.D. dependent var

2541.893

S.E. of regression

933.2830

    Akaike info criterion

16.60993

Sum squared resid

39195776

    Schwarz criterion

16.80114

Log likelihood

-410.2483

    Hannan-Quinn criter.

16.68274

F-statistic

79.62067

    Durbin-Watson stat

1.967556

Prob(F-statistic)

0.000000

    Wald F-statistic

21.47470

Prob(Wald F-statistic)

0.000000

REVISED: THEORY OF DEMAND QELEC/HOUSING = C(1)*PELEC + C(2)*PGAS + C(3)*INCOME/HOUSING + C(4)

C(1) –

C(2) +

C(3) +

C(4) no expectation

Dependent Variable: QELEC/HOUSING

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

PELEC

-6.94E-05

1.46E-05

-4.750072

0.0000

PGAS

2.06E-05

1.41E-05

1.466870

0.1492

INCOME/HOUSING

-0.000327

0.002383

-0.137055

0.8916

C

0.001784

0.000217

8.223864

0.0000

R-squared

0.549799

    Mean dependent var

0.001091

Adjusted R-squared

0.520438

    S.D. dependent var

0.000341

S.E. of regression

0.000236

    Akaike info criterion

-13.78950

Sum squared resid

2.56E-06

    Schwarz criterion

-13.63654

Log likelihood

348.7375

    Hannan-Quinn criter.

-13.73125

F-statistic

18.72553

    Durbin-Watson stat

2.016181

Prob(F-statistic)

0.000000

    Wald F-statistic

18.67201

Prob(Wald F-statistic)

0.000000

3. Re-estimate the equation to see if there is a quadratic effect for income and paste the output in your assignment.

Dependent Variable: QELEC

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

PELEC

-137.1613

52.17824

-2.628706

0.0118

PGAS

80.63222

49.84062

1.617801

0.1129

INCOME

-0.000579

0.003924

-0.147580

0.8833

INCOME^2

-2.01E-09

7.26E-10

-2.770709

0.0082

HOUSING

0.001283

0.000387

3.314235

0.0018

C

806.2214

314.7208

2.561703

0.0139

R-squared

0.894377

    Mean dependent var

2726.780

Adjusted R-squared

0.882375

    S.D. dependent var

2541.893

S.E. of regression

871.7807

    Akaike info criterion

16.49112

Sum squared resid

33440071

    Schwarz criterion

16.72056

Log likelihood

-406.2780

    Hannan-Quinn criter.

16.57849

F-statistic

74.51553

    Durbin-Watson stat

2.059782

Prob(F-statistic)

0.000000

    Wald F-statistic

19.59777

Prob(Wald F-statistic)

0.000000

Dependent Variable: QELEC/HOUSING

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

PELEC

-6.93E-05

1.47E-05

-4.722351

0.0000

PGAS

2.07E-05

1.41E-05

1.465375

0.1498

INCOME/HOUSING

0.001132

0.018876

0.059950

0.9525

(INCOME/HOUSING)^2

-0.006353

0.082070

-0.077403

0.9386

C

0.001703

0.001061

1.605227

0.1154

R-squared

0.549894

    Mean dependent var

0.001091

Adjusted R-squared

0.509885

    S.D. dependent var

0.000341

S.E. of regression

0.000239

    Akaike info criterion

-13.74971

Sum squared resid

2.56E-06

    Schwarz criterion

-13.55851

Log likelihood

348.7428

    Hannan-Quinn criter.

-13.67690

F-statistic

13.74414

    Durbin-Watson stat

2.023571

Prob(F-statistic)

0.000000

    Wald F-statistic

13.82124

Prob(Wald F-statistic)

0.000000

4. Interpret the coefficients for income and calculate where the parabola turns.

When income changes by one unit(one million dollars) ( I chose to do it from the means of all the data to the mean + 1 for income), QELEC changes by .001739 million kilowatthours

GENR CHANGE_QELEC2 = (c(3)*@mean(INCOME)+c(4)*@mean(INCOME)^2)-(c(3)*(@mean(INCOME) +1)+c(4)*(@mean(INCOME)+1)^2)

To find where the parabola turns take the partial derivative wrt incomeand set it equal to 0 and solver for INCOME=-5.28E-13 (very slightly below the origin)

Revised: When income changes by one unit(one million dollars) ( I chose to do it from the means of all the data to the mean + 1 for income), QELEC changes by 3664.19 million kilowatthours per household.

The parabola turns at 3.59E-06

5. Describe the procedure you should use to determine how high a power of income should be included in the equation.

Start with the highest power you think could be in the equation (I use 4th power). Test to see if the highest powers is statistically significantly different form zero (is the p-value below .05). If not drop that power and re-estimate with a lower power. Test the highest power coefficient,. Etc. until you have found the highest significant power. The fourth power is significant.

Revised. The fourth power is not significant but the third power is.

6. Re-estimate the equation of #3 in log-log form and paste the results in your assignment.

With my data the income squared term caused multicollinearity so I deleted it.

Dependent Variable: LOG(QELEC)

Method: Least Squares

Date: 04/09/15 Time: 12:40

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

LOG(PELEC)

-1.014908

0.147823

-6.865699

0.0000

LOG(PGAS)

0.058667

0.128630

0.456089

0.6505

LOG(INCOME)

-0.063944

0.208747

-0.306321

0.7608

LOG(HOUSING)

1.058285

0.212936

4.969967

0.0000

C

-4.542955

0.748159

-6.072176

0.0000

R-squared

0.968086

    Mean dependent var

7.447635

Adjusted R-squared

0.965249

    S.D. dependent var

1.069879

S.E. of regression

0.199443

    Akaike info criterion

-0.291940

Sum squared resid

1.789983

    Schwarz criterion

-0.100738

Log likelihood

12.29850

    Hannan-Quinn criter.

-0.219129

F-statistic

341.2581

    Durbin-Watson stat

2.079090

Prob(F-statistic)

0.000000

    Wald F-statistic

477.6741

Prob(Wald F-statistic)

0.000000

Dependent Variable: LOG(QELEC/HOUSING)

Method: Least Squares

Date: 04/11/15 Time: 10:12

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

C

-4.631142

0.587478

-7.883086

0.0000

LOG(PELEC)

-1.014415

0.147011

-6.900267

0.0000

LOG(PGAS)

0.059788

0.127858

0.467613

0.6423

LOG(INCOME/HOUSING)

-0.065418

0.204341

-0.320142

0.7503

R-squared

0.686380

    Mean dependent var

-6.873730

Adjusted R-squared

0.665927

    S.D. dependent var

0.341443

S.E. of regression

0.197351

    Akaike info criterion

-0.331050

Sum squared resid

1.791576

    Schwarz criterion

-0.178088

Log likelihood

12.27625

    Hannan-Quinn criter.

-0.272801

F-statistic

33.55814

    Durbin-Watson stat

2.064927

Prob(F-statistic)

0.000000

7. Evaluate your results including your estimate of the own price elasticity of demand

1a. Own price elasticity is just coefficient of LOG(PELEC) = -1.04, so demand is elastic.

1b. The r-quare is 0.968086, which improved a lot BUT because the dependent variables are different the two R-squareds are not comparable.

Revised 1 The own elasticity is just coefficient of log(PELEC) = -1.014415, so demand is elastic

Revised 2. The r-square is 0.686380, which improved from the previous regression. BUT because the dependent variables are different the two R-squareds are not comparable.

8. Which is better, the linear model or the log-log model? Calculate the predicted values of consumption for each of the states and use these values to construct an approximate R-square to compare with the one from the linear model.

R-squared from the linear regression = 0.876198, for the log-log model a roughly comparable R-Square is computed as follows:

GENR LOG_QELEC_HAT= -1.01490807904*LOG(PELEC) + 0.0586667432728*LOG(PGAS) - 0.0639435179339*LOG(INCOME) + 1.05828529565*LOG(HOUSING) - 4.54295469693

GENR QELEC_HAT=EXP( LOGQELEC_HAT)

GENR R_squared = 1 - @SUMSQ(QELEC-QELECHAT)/@SUMSQ(QELEC-@MEAN(QELEC))=.934672 which is better

REVISED R-squared from the linear regression = 0.558977, from the log-log model a roughly comparable R-Square is computed as follows:

GENR LOG_QELEC_P_HAT -1.01441518281*LOG(PELEC) + 0.0597882688648*LOG(PGAS) - 0.0654180887821*LOG(INCOME/HOUSING) - 4.63114153304

GENR QELEC_P_HAT=EXP( LOG_QELEC_P_HAT)

GENR R_squared_REVISED= 1 - @SUMSQ(QELEC/HOUSING-QELEC_p_HAT)/@SUMSQ(QELEC/HOUSING-@MEAN(QELEC/HOUSING))=.662213 which is better

9. Re-estimate the linear model using the ratio of electric to natural gas prices and paste the results in your assignment.

Dependent Variable: QELEC

Method: Least Squares

Date: 04/11/15 Time: 14:14

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

C

1108.287

630.1472

1.758776

0.0853

PELEC/PGAS

-752.8126

477.4749

-1.576654

0.1217

INCOME

-0.008921

0.003179

-2.806252

0.0073

HOUSING

0.001955

0.000395

4.942812

0.0000

R-squared

0.871187

    Mean dependent var

2726.780

Adjusted R-squared

0.862786

    S.D. dependent var

2541.893

S.E. of regression

941.5783

    Akaike info criterion

16.60961

Sum squared resid

40782209

    Schwarz criterion

16.76257

Log likelihood

-411.2403

    Hannan-Quinn criter.

16.66786

F-statistic

103.7021

    Durbin-Watson stat

2.001158

Prob(F-statistic)

0.000000

Dependent Variable: QELEC/HOUSING

Method: Least Squares

Date: 04/11/15 Time: 14:14

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

C

0.002021

0.000225

8.985315

0.0000

PELEC/PGAS

-0.000421

0.000154

-2.737523

0.0087

INCOME/HOUSING

-0.003864

0.002411

-1.602961

0.1156

R-squared

0.278478

    Mean dependent var

0.001091

Adjusted R-squared

0.247775

    S.D. dependent var

0.000341

S.E. of regression

0.000295

    Akaike info criterion

-13.35783

Sum squared resid

4.10E-06

    Schwarz criterion

-13.24311

Log likelihood

336.9458

    Hannan-Quinn criter.

-13.31414

F-statistic

9.070038

    Durbin-Watson stat

2.089905

Prob(F-statistic)

0.000467

10. Evaluate this model in comparison with the original one.

R-squared does not change too much.

R-squared decreased significantly.

11. Is the consumption behavior different (i.e., do prices, incomes and housing units have different effects) in sates with incomes higher than the average? Estimate an equation that will let you determine this and paste the results in your assignment.

GENR DUMMY=0

SMPL IF INCOME>@MEAN(INCOME)

GENR DUMMY=1

SMPL @ALL

Dependent Variable: QELEC

Method: Least Squares

Date: 04/11/15 Time: 14:14

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

C

1109.788

362.2704

3.063425

0.0037

PELEC

-109.6877

51.59186

-2.126066

0.0391

PGAS

50.00712

50.39281

0.992346

0.3265

INCOME

-0.007551

0.002904

-2.600184

0.0126

HOUSING

0.001689

0.000376

4.496999

0.0000

DUMMY

763.8297

428.3546

1.783172

0.0815

R-squared

0.884855

    Mean dependent var

2726.780

Adjusted R-squared

0.871771

    S.D. dependent var

2541.893

S.E. of regression

910.2296

    Akaike info criterion

16.57744

Sum squared resid

36454785

    Schwarz criterion

16.80688

Log likelihood

-408.4359

    Hannan-Quinn criter.

16.66481

F-statistic

67.62556

    Durbin-Watson stat

1.934518

Prob(F-statistic)

0.000000

Dependent Variable: QELEC/HOUSING

Method: Least Squares

Date: 04/11/15 Time: 14:14

Sample (adjusted): 1 51

Included observations: 50 after adjustments

White heteroskedasticity-consistent standard errors & covariance

Variable

Coefficient

Std. Error

t-Statistic

Prob.  

C

0.001778

0.000230

7.720086

0.0000

PELEC

-6.94E-05

1.48E-05

-4.704281

0.0000

PGAS

2.06E-05

1.41E-05

1.462455

0.1506

INCOME/HOUSING

-0.000229

0.002652

-0.086406

0.9315

DUMMY

-1.28E-05

7.56E-05

-0.168668

0.8668

R-squared

0.550068

    Mean dependent var

0.001091

Adjusted R-squared

0.510074

    S.D. dependent var

0.000341

S.E. of regression

0.000238

    Akaike info criterion

-13.75010

Sum squared resid

2.56E-06

    Schwarz criterion

-13.55889

Log likelihood

348.7524

    Hannan-Quinn criter.

-13.67729

F-statistic

13.75376

    Durbin-Watson stat

2.014425

Prob(F-statistic)

0.000000

12. Are there a differences? (Interpret all of the coefficients)

Wald Test:

Equation: BEHAVIOR_DIFFERENCE

Test Statistic

Value

df

Probability

t-statistic

 1.783172

 44

 0.0815

F-statistic

 3.179701

(1, 44)

 0.0815

Chi-square

 3.179701

 1

 0.0746

Null Hypothesis: C(6)=0

Null Hypothesis Summary:

Normalized Restriction (= 0)

Value

Std. Err.

C(6)

 763.8297

 428.3546

Restrictions are linear in coefficients.

Wald Test:

Equation: BEHAVIOR_DIFFERENCE_REVI

Test Statistic

Value

df

Probability

t-statistic

-0.168668

 45

 0.8668

F-statistic

 0.028449

(1, 45)

 0.8668

Chi-square

 0.028449

 1

 0.8661

Null Hypothesis: C(5)=0

Null Hypothesis Summary:

Normalized Restriction (= 0)

Value

Std. Err.

C(5)

-1.28E-05

 7.56E-05

Restrictions are linear in coefficients.

Wald test doesn’t reject h0 that dummy=0 at 5% significant level, indicating that there is no difference in consumer behavior. However, it does reject h0 at 10% significant level, which suggests there is a difference.

Wald test doesn’t reject h0 that dummy=0 at 5% significant level, indicating that there is no difference in consumer behavior.

13. Save your workfile as YourLastNameFirstName.wf1. Send a copy to the assistant.