assist (version 2.0)

horm.cort: Hormone Measurements of Cortisol

Description

The horm.cort data frame has 425 rows and 4 columns of data representing measurement of cortisol on 36 individuals.

Usage

data(horm.cort)

format

The data frame contains the following columns:

ID a vector of index indicating individuals on whom measures were made.

time a numeric vector of time points of every 2 hours in 24 hours. The time is scaled into [0, 1].

type a vector of character strings identifying the groups, "normal", "depressed", or "cushing", which the individuals belong to.

conc cortisol concentration measurements in $log10$ scale.

source

This data set was extracted from a stress study conducted in the medical center of the University of Michigan.

Details

Blood samples were collected every 2 hours for 24 hours from three group of healthy normal volunteers and volunteers with depresession and suchsing syndrome. They were analyzed for parameters that measure hormones of the hypothalamic-pituitary axix. Human circadian thythm is one of the research objective. In this data set, only measurements of cortisol concetration were included.

References

Wang, Y. and Brown, M. B. (1996). A Flexible Model for Human Circadian Rhythms. Biometrics 52, 588-596.

Yuedong Wang, Chunlei Ke and Morton B. Brown (2003), Shape Invariant Modelling of Circadian Rhythms with Random Effects and Smoothing Spline ANOVA Decompositions. Biometrics, 59:804-812.