Hello, Dear all:

I am doing this regression lm by each patient ID. Then try to calculate confidence interval for coefficient. I got this error message in the end.

fitted_models = df31 %>% group_by(PatId) %>% do(model = lm(var1 ~ yr_findex, data = .))

t<- fitted_models%>%group_by(PatId) %>% do(confint(., "yr_findex", level=0.80))

Then I always this error as

Error in UseMethod("vcov") :

no applicable method for 'vcov' applied to an object of class "c('tbl_df', 'tbl', 'data.frame')"

Anyone knows why? I am a SAS newly converted R user...so still asking very simple questions here. Thanks a lot!