Pixel Intensity Data

SUMMARY:

Mean pixel intensity of the right and left lymphnodes in the axillary region obtained from CT scans of 10 dogs over a period of 14 days after intravenous application of a contrast.

DATA DESCRIPTION:

This data frame contains the following columns:

VALUE:

Dog
a factor giving the unique identifier for each dog.
Side
a factor indicating the side on which the measurement was made.
day
number of days since contrast administration.
pixel
mean pixel intensity of lymphnode in the CT scan.

SOURCE:

These data are from an experiment conducted by Deborah Darien, Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison.

SEE ALSO:

, .

EXAMPLES:

Pixel$Side.r <- as.integer(Pixel$side == "r") 
Pixel$Side.l <- as.integer(Pixel$side == "l") 
Pixel.lme <- lme(fixed = pixel ~ day + day^2,  
                 random = ~ Side.r + Side.l + day, 
                 cluster = ~ Dog, data = Pixel)