A data.frame with 6 columns ("Low", "Mid", "High", "Time",
"Cov", "Model")
, where "Mid"
is the point estimates;
"Low"
and "High"
are the point estimates plus and minus
1.96 times standard deviations (under default level); "Cov"
and
"Model"
contain character values of the covariates and model
type.