Format
A data frame with 90 observations on the following 3 variables.
  
    meth- a factor with levels 
Gerber Trig  item- sample id
  y- a numeric vector
  
 Source
The dataset is adapted from table 3 in: JM Bland and DG Altman: Measuring
 agreement in method comparison studies. Statistical Methods in Medical
 Research, 8:136-160, 1999. See: Lucas A, Hudson GJ, Simpson P, Cole TJ,
 Baker BA. An automated enzymic micromethod for the measurement of fat in human
 milk. Journal of Dairy Research 1987; 54: 487-92.