Using R and the package "faraway"... data(fat, package="faraway")

> lmod <- lm(brozek~age+weight+height+neck+chest+abdom+hip+thigh+knee+ankle+biceps+forearm+wrist, data=fat)

For the fat data used in class, a smaller model using only age, weight, height, and abdom was proposed on the grounds that these predictors are either known by the individual or easily measured.

Compute a 95% condence interval for median predictor values and compare to the results to the interval for the full model which contains all the predictor variables.

Compute a 90% prediction interval for median predictor values. Is the interval wider or narrower comparing to the condence interval on mean response at the same condence level? Please help me with the R code for these questions.