clotting: Blood clotting for 158 rats

In MESS: Miscellaneous Esoteric Statistical Scripts

Blood clotting for 158 rats

Description

Blood clotting activity (PCA) is measured for 158 Norway rats from two locations just before (baseline) and four days after injection of an anticoagulant (bromadiolone). Normally this would cause reduced blood clotting after 4 days compared to the baseline, but these rats are known to possess anticoagulent resistence to varying extent. The purpose is to relate anticoagulent resistence to gender and location and perhaps weight. Dose of injection is, however, admistered according to weight and gender.

Format

A data frame with 158 observations on the following 6 variables.

rat

a numeric vector

locality

a factor with levels Loc1 Loc2

sex

a factor with levels F M

weight

a numeric vector

PCA0

a numeric vector with percent blood clotting activity at baseline

PCA4

a numeric vector with percent blood clotting activity on day 4

Source

Ann-Charlotte Heiberg, project at The Royal Veterinary and Agricultural University, 1999.
Added by Ib M. Skovgaard <[e-mail]>

Examples

 data(clotting)
 dim(clotting)
 head(clotting)
 day0= transform(clotting, day=0, pca=PCA0)
 day4= transform(clotting, day=4, pca=PCA4)
 day.both= rbind(day0,day4)
 m1= lm(pca ~ rat + day*locality + day*sex, data=day.both)
 anova(m1)
 summary(m1)
 m2= lm(pca ~ rat + day, data=day.both)
 anova(m2)
## Log transformation suggested.
## Random effect of rat.
## maybe str(clotting) ; plot(clotting) ...

MESS documentation built on Aug. 21, 2023, 1:05 a.m.