Last week I listened to a great presentation about new trial designs by Mahesh Parmar, director of the Medical Research Council Clinical Trial Unit in London. Among the topics he touched on were multi-arm trials (and extensions), as an attractive alternative to the classic two arm trial. There seem to be a number of advantages to such a trial design, in which in the simplest case, the trial randomizes patients to either control or one of a number of experimental treatments.
Jonathan Bartlett
R squared/correlation depends on variance of predictor
I’ve written about R squared a few times before. In a discussion I was involved with today the question was raised as to how/whether the R squared in a linear regression model with a single continuous predictor depends on the variance of the predictor variable. The answer to the question is of course yes.
My first foray with Stan
A number of people have mentioned Stan recently to me. Stan fits probability models to data using the Bayesian approach to statistical inference. WinBUGS was the first package to really allow users to fit complex, user defined models with Bayesian methods. As far as I understand, Stan’s strongest selling points are that it is fast, because it compiles your model into C++ code, and because of the clever sampling methods it implements (for more on this, see the sub-section in Stan’s manual).