I am using the ggpredict function to get the predicted values of height with x, predicted, std.error, conf.low, and conf.high (shown in the screenshot below)

pred_height<-as.data.frame(ggpredict(modfit, terms="height", typical="mean", back.transform=FALSE))

I used quantile(pred_height$predicted) to obtain the 75th percentile and the 25th percentile predicted values. However, I can get the corresponding standard errors of the 25th and the 75th percentile predicted by using quantile(std.error). I’d like to know how to get the corresponding SEs? Many thanks!