Econometrics-I-12

# 2038 part 12 asymptotics for the regression model

• Notes
• 39

This preview shows page 21 - 29 out of 39 pages.

™  20/38

Subscribe to view the full document.

Part 12: Asymptotics for the Regression Model General Result for Wald Distance The Wald distance measure: If plim xn = , xn is asymptotically normally distributed with a mean of and variance , and if S n is a consistent estimator of , then the Wald statistic, which is a generalized distance measure between x n converges to a chi- squared variate. ( x n - ) Sn-1 ( x n - )  2[K] ™  21/38
Part 12: Asymptotics for the Regression Model The F Statistic An application: (Familiar) Suppose b n is the least squares estimator of based on a sample of n observations. No assumption of normality of the disturbances or about nonstochastic regressors is made. The standard F statistic for testing the hypothesis H0: R - q = 0 is F[J, n-K] = [( e*’e* - e’e )/J] / [ e’e / (n-K)] where this is built of two sums of squared residuals. The statistic does not have an F distribution. How can we test the hypothesis? ™  22/38

Subscribe to view the full document.

Part 12: Asymptotics for the Regression Model JF is a Wald Statistic F[J,n-K] = (1/J)  ( Rbn - q ) [ R s2( XX )-1 R’ ]-1 ( Rbn - q ). Write m = ( Rbn - q ). Under the hypothesis, plim m = 0 . n m  N[0, R (2/n) Q -1 R ’] Estimate the variance with R (s2/n)( X’X /n)-1 R ’] Then, (n m )’ [Est.Var(n m )]-1 (n m ) fits exactly into the apparatus developed earlier. If plim b n = , plim s2 = 2, and the other asymptotic results we developed for least squares hold, then JF[J,n-K]  2[J]. ™  23/38
Part 12: Asymptotics for the Regression Model Application: Wald Tests read;nobs=27;nvar=10;names= Year, G , Pg, Y , Pnc , Puc , Ppt , Pd , Pn , Ps \$ 1960 129.7 .925 6036 1.045 .836 .810 .444 .331 .302 1961 131.3 .914 6113 1.045 .869 .846 .448 .335 .307 1962 137.1 .919 6271 1.041 .948 .874 .457 .338 .314 1963 141.6 .918 6378 1.035 .960 .885 .463 .343 .320 1964 148.8 .914 6727 1.032 1.001 .901 .470 .347 .325 1965 155.9 .949 7027 1.009 .994 .919 .471 .353 .332 1966 164.9 .970 7280 .991 .970 .952 .475 .366 .342 1967 171.0 1.000 7513 1.000 1.000 1.000 .483 .375 .353 1968 183.4 1.014 7728 1.028 1.028 1.046 .501 .390 .368 1969 195.8 1.047 7891 1.044 1.031 1.127 .514 .409 .386 1970 207.4 1.056 8134 1.076 1.043 1.285 .527 .427 .407 1971 218.3 1.063 8322 1.120 1.102 1.377 .547 .442 .431 1972 226.8 1.076 8562 1.110 1.105 1.434 .555 .458 .451 1973 237.9 1.181 9042 1.111 1.176 1.448 .566 .497 .474 1974 225.8 1.599 8867 1.175 1.226 1.480 .604 .572 .513 1975 232.4 1.708 8944 1.276 1.464 1.586 .659 .615 .556 1976 241.7 1.779 9175 1.357 1.679 1.742 .695 .638 .598 1977 249.2 1.882 9381 1.429 1.828 1.824 .727 .671 .648 1978 261.3 1.963 9735 1.538 1.865 1.878 .769 .719 .698 1979 248.9 2.656 9829 1.660 2.010 2.003 .821 .800 .756 1980 226.8 3.691 9722 1.793 2.081 2.516 .892 .894 .839 1981 225.6 4.109 9769 1.902 2.569 3.120 .957 .969 .926 1982 228.8 3.894 9725 1.976 2.964 3.460 1.000 1.000 1.000 1983 239.6 3.764 9930 2.026 3.297 3.626 1.041 1.021 1.062 1984 244.7 3.707 10421 2.085 3.757 3.852 1.038 1.050 1.117 1985 245.8 3.738 10563 2.152 3.797 4.028 1.045 1.075 1.173 1986 269.4 2.921 10780 2.240 3.632 4.264 1.053 1.069 1.224 ™  24/38

Subscribe to view the full document.

Part 12: Asymptotics for the Regression Model Data Setup Create; G=log(G); Pg=log(PG); y=log(y); pnc=log(pnc); puc=log(puc); ppt=log(ppt); pd=log(pd); pn=log(pn); ps=log(ps); t=year-1960\$ Namelist; X=one,y,pg,pnc,puc,ppt,pd,pn,ps,t\$ Regress; lhs=g;rhs=X;PrintVC\$ ™  25/38
Part 12: Asymptotics for the Regression Model Regression Model Based on the gasoline data: The regression equation is g =1 + 2y + 3pg + 4pnc + 5puc + 6ppt + 7pd + 8pn + 9ps + 10t +  All variables are logs of the raw variables, so that coefficients are elasticities. The new variable, t, is a time trend, 0,1,…,26, so that 10 is the autonomous yearly proportional growth in G. ™  26/38

Subscribe to view the full document.

Part 12: Asymptotics for the Regression Model Least Squares Results +----------------------------------------------------+ | Ordinary least squares regression | | LHS=G Mean = 5.308616 | | Standard deviation = .2313508 | | Model size Parameters = 10 | | Degrees of freedom = 17 | | Residuals Sum of squares = .003776938 | | Standard error of e = .01490546 | | Fit R-squared = .9972859 | | Adjusted R-squared = .9958490 | | Model test F[ 9, 17] (prob) = 694.07 (.0000) | | Chi-sq [ 9] (prob) = 159.55 (.0000) | +----------------------------------------------------+ +---------+--------------+----------------+--------+---------+----------+ |Variable | Coefficient | Standard Error |t-ratio |P[|T|>t] | Mean of X| +---------+--------------+----------------+--------+---------+----------+ Constant -5.97984140 2.50176400 -2.390 .0287 Y 1.39438363 .27824509 5.011 .0001 9.03448264 PG -.58143705 .06111346 -9.514 .0000 .47679491

{[ snackBarMessage ]}

###### "Before using Course Hero my grade was at 78%. By the end of the semester my grade was at 90%. I could not have done it without all the class material I found."
— Christopher R., University of Rhode Island '15, Course Hero Intern

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern