Econometrics Case 3.8 Wooldridge
4) [Wooldridge C3.8]
(i)
Wiew/Descriptive statistics
INCOME PRPBLCK Mean 47053.78 0.113486 Median 46272.00 0.041444 Maximum 136529.0 0.981658 Minimum 15919.00 0.000000 Std. Dev. 13179.29 0.182416 Skewness 0.962831 2.700012 Kurtosis 7.551386 10.56841 Jarque-Bera 416.2135 1473.100 Probability 0.000000 0.000000 Sum 19244998 46.41594 Sum Sq. Dev. 7.09E+10 13.57651 Observations 409 409
The average of prpblck is .113 with standard deviation .182; the average of income is 47,053.78 with standard deviation 13,179.29. It is evident that prpblck is a proportion and that income is measured in dollars.
(ii)
Dependent Variable: PSODA
Method: Least Squares
Sample: 1 410
Included observations: 401
Excluded observations: 9
Variable Coefficient Std. Error t-Statistic Prob.
PRPBLCK 0.114988 0.026001 4.422515 0.0000
INCOME 1.60E-06 3.62E-07 4.430130 0.0000
C 0.956320 0.018992 50.35379 0.0000
R-squared 0.064220 Mean dependent var 1.044863
Adjusted R-squared 0.059518 S.D. dependent var 0.088798
S.E. of regression 0.086115 Akaike info criterion -2.058820
Sum squared resid 2.951465 Schwarz criterion -2.028940
Log likelihood 415.7934 F-statistic 13.65691
Durbin-Watson stat 1.696180 Prob(F-statistic) 0.000002
If, say, prpblck increases by .10 (ten percentage points), the price of soda is estimated to increase by .0115 dollars, or about 1.2 cents, holding income constant. While this does not seem large, there are communities with no black population and others that are almost all black, in which case the difference in psoda is estimated to be almost 11.5 cents. I’d still say it’s pretty weak effect, but it’s not totally negligible, given that the price of soda is pretty low.
(iii)
Dependent Variable: PSODA
Method: Least Squares
Sample: 1 410
Included observations: 401
Excluded observations: 9
Variable Coefficient Std. Error t-Statistic Prob.
PRPBLCK
(i)
Wiew/Descriptive statistics
INCOME PRPBLCK Mean 47053.78 0.113486 Median 46272.00 0.041444 Maximum 136529.0 0.981658 Minimum 15919.00 0.000000 Std. Dev. 13179.29 0.182416 Skewness 0.962831 2.700012 Kurtosis 7.551386 10.56841 Jarque-Bera 416.2135 1473.100 Probability 0.000000 0.000000 Sum 19244998 46.41594 Sum Sq. Dev. 7.09E+10 13.57651 Observations 409 409
The average of prpblck is .113 with standard deviation .182; the average of income is 47,053.78 with standard deviation 13,179.29. It is evident that prpblck is a proportion and that income is measured in dollars.
(ii)
Dependent Variable: PSODA
Method: Least Squares
Sample: 1 410
Included observations: 401
Excluded observations: 9
Variable Coefficient Std. Error t-Statistic Prob.
PRPBLCK 0.114988 0.026001 4.422515 0.0000
INCOME 1.60E-06 3.62E-07 4.430130 0.0000
C 0.956320 0.018992 50.35379 0.0000
R-squared 0.064220 Mean dependent var 1.044863
Adjusted R-squared 0.059518 S.D. dependent var 0.088798
S.E. of regression 0.086115 Akaike info criterion -2.058820
Sum squared resid 2.951465 Schwarz criterion -2.028940
Log likelihood 415.7934 F-statistic 13.65691
Durbin-Watson stat 1.696180 Prob(F-statistic) 0.000002
If, say, prpblck increases by .10 (ten percentage points), the price of soda is estimated to increase by .0115 dollars, or about 1.2 cents, holding income constant. While this does not seem large, there are communities with no black population and others that are almost all black, in which case the difference in psoda is estimated to be almost 11.5 cents. I’d still say it’s pretty weak effect, but it’s not totally negligible, given that the price of soda is pretty low.
(iii)
Dependent Variable: PSODA
Method: Least Squares
Sample: 1 410
Included observations: 401
Excluded observations: 9
Variable Coefficient Std. Error t-Statistic Prob.
PRPBLCK