why do I get different heteroscadisity robust standard errors in r? what is lm.model what is the difference between lm.model and plm.model why does r generate robust standard error why do r tests have different robust standard errors why does r get standard errors why r has variable fixed and entity fixed errors what is plm standard error which package is used to test heteroscadisity robust standard errors? what is lm standard error what is lm model? why is plm error different from lm what is the standard error in plm package what is lm.model? why is it wrong to use the plm package why is r a heteroscedastic standard error why does r have different standard error models how to test heteroscedasticity robust standard errors why do r models have standard errors how to get heteroscedastic standard errors in r