[R] Help with problem - multilevel model?

I have what is probably a very simple problem but I would be very grateful to the list for any help or pointers to implement a solution in R. We have two types of measurements on the eye that we have collected in 62 patients at 5 fixed time points during a clinical visit over an office day. We

[R] bilinear regression

I think this is an easy question, but I would be grateful for any advice on how to implement this in R. I simply have a response variable (y) that I am trying to predict with one explanatory variable (x) but the shape of the scatter plot is distinctly bilinear. It would be best described by two

[R] normal reference intervals

I am interested in calculating Age-Specific normal reverence intervals, using non-parametric methods - or ideally something called the LMS method (which as I understand it uses cubic splines fitted to the data). Any packages in R that you think might help me? Any other advice gratefully received.

[R] Query: simple autocorrelation ina time series

I hope you can help with what might be an easy query. I am doing some simple simulations where I am generating series of data from a normal distribution using rnorm. I am then treating these as a time series. I want to know how I can incorporate correlation in the series (autocorrelation) i.e.

[R] Residuals, smoothers and estimates of noise

We have a clinical measurement on patients over time. Each patient has about 5 of these measurements over a period of two years, but the measurement are not necessarily taken at equal space in time. We want to use this data to establish test-retest variability. My first thought was to look at the

[R] Help with generating data from a 'not quite' Normal distriburtion

I would be very grateful for any help from members of this list for what might be a simple problem... We are trying to simulate the behaviour of a clinical measurement in a series of computer experiments. This is simple enough to do in R if we assume the measurements to be Gaussian, but their

[R] Help with Normal Range Estimation for repated measures

I would be grateful if members of the list could point me in the direction of any code (preferably in R) that will allow me to estimate 95th percentiles from a set of repeated measurements. For example, we are interested in a clinical measurement where we have 3 measures for 14 subjects and 2