John: If the separation is clear on the scatter plots then there is no need to do anything else.
John G. wrote: >Hi everyone > >I need some help comparing curves generated from an experiment >examining ecto-parasite loads on fish. > >A number of individuals were infected and the number of parasites >counted on each fish five times over the next 30 days. The fish showed >three basic patterns of response to the initial infection. The first >group showed an exponential-like growth of parasites until the end of >the experiment (we call these susceptible). The second group showed an >initial increase in numbers until around the mid-point after which the >numbers dropped, sometimes to zero but usually to low levels (the >curve looks like a hill or dome) (resistant type 1). The final group >seemed to retain a low load throughout the experiment, neither >increasing or decreasing (resistant type 2). > >I want to be able to do two things with this data. Firstly, I would >like to be able to split the fish into the three groups mentioned >above using stats, not charts. Secondly, I would like to generate some >value/s which I could use as a guide to ‘strength of >response’. In this case I would imagine getting something like a >high value for resistant type 1 as they show a definite and strong >response, this might be followed by a medium value for resistant type >2 as although they did not reduce the parasite load, it was prevented >from increasing to high levels, and finally a low value for the >susceptible group as they showed no response at all. > >Please help. I have played with fitting and comparing various curves, >putting the data through PCA etc but am having no luck achieving my >two aims. > >Thanks in advance >John G > > . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
