search for: ludbrook

Hello all, How do I actually use the output of predict.lm(..., type="terms") to predict new term values from new response values? I'm a chromatographer trying to use R (2.15.1) for one of the most common calculations in that business: - Given several chromatographic peak areas measured for control samples containing a molecule at known (increasing) concentrations, first

...'day, My problem is I'm not sure how to extract effect sizes from a nonlinear regression model with a significant interaction term. My data sets are multiple measurements of force response to an agonist with two superimposed treatments each having two levels. This is very similar to the Ludbrook example in Venables and Ripley. The experiment is that a muscle is exposed to an agonist and the force response is measured. The resulting data is fit to a logistic fit (a three parameter rather than the four parameter used by Ludbrook) . This is done for each combination of two factors (treatm...

...#39;ve been performing an analysis of some data by a follow the leader method (Bad I know but it seems to work and I think I understand all the steps now) and I''ve run into a problem. The analysis is for all practical purposes identical to the non-linear mixed effects analysis performed on Ludbrooks Rabbit data in the second edition of Venables & Ripley (page 315--321). I have the stats pretty much done and have estimates for all the model parameters from the nlme object. Now I want to add the fitted lines to my coplot of the data in the manner of figure 10.3. How would I do this? I owu...

...8 replicates for each combination of treatments We fit a dose response curve to each experiment with parameters upper, ed50 and slope; we expect treatment A to change upper and ed50. We want to know if treatment B blocks the effect of treatment A and if so to what degree. This is similar to the Ludbrook example in Venables and Ripley, however they only had one treatment and I have two. my approach The dataframe is structured like this: expt treatA treatB dose force. 1 - - 0.1 20 1 - - 0.2 40 ... 4 + + 0.1 20 4 + I used a groupedData object: mydata=groupedData(force ~ dose | expt)...

Dear all, Does any one know if any R package or function can do Ordinary Least Products regression? Many thanks! Bill