Anyone using Wooldrige's Introductory Econometrics: A Modern Approach? In the 3rd edition example 8.3, I use the following method to compute heteroskedasticity-robust LM statistic
library(car) linear.hypothesis(model,c("avgsen=0","I(avgsen^2)=0") ,test="Chisq",vcov=hccm(model,type="hc0")) The result is different from the one introduced in the text. The p-value is also differ greatly from using heteroskedasticity-robust F statistic. Any thought on this? -- View this message in context: http://n4.nabble.com/How-to-compute-heteroskedasticity-robust-LM-statistic-tp1558305p1558305.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.