plvol {MethComp}

Measurements of plasma volume measured by two different methods.

Description

For each subject (item) the plasma volume is expressed as a percentage of the expected value for normal individuals. Two alternative sets of normal values are used, named Nadler and Hurley respectively.

Format

A data frame with 198 observations on the following 3 variables.

meth

a factor with levels Hurley and Nadler

item

a numeric vector

y

a numeric vector

Source

The datset is adapted from table 2 in: JM Bland and DG Altman: Measuring agreement in method comparison studies. Statistical Methods in Medical Research, 8:136-160, 1999. Originally supplied to Bland \& Altman by C Dore, see: Cotes PM, Dore CJ, Liu Yin JA, Lewis SM, Messinezy M, Pearson TC, Reid C. Determination of serum immunoreactive erythropoietin in the investigation of erythrocytosis. New England Journal of Medicine 1986; 315: 283-87.

Examples

data(plvol)
str(plvol)
plot( y[meth=="Nadler"]~y[meth=="Hurley"],data=plvol,
      xlab="Plasma volume (Hurley) (pct)",
      ylab="Plasma volume (Nadler) (pct)" )
abline(0,1)
par( mar=c(4,4,1,4) )
BA.plot(plvol)