milk: Measurement of fat content of human milk by two different...

In MethComp: Analysis of Method Comparison studies

Description

Fat content of human milk determined by measurement of glycerol released by enzymic hydrolysis of triglycerides (Trig) and measurement by the Standard Gerber method (Gerber). Units are (g/100 ml).

Usage

data(milk)

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.

Examples

data(milk)
str(milk)
milk <- Meth(milk)
plot(milk)
abline(0,1)

Example output

Loading required package: nlme
'data.frame':	90 obs. of  3 variables:
 $ meth: Factor w/ 2 levels "Gerber","Trig": 2 2 2 2 2 2 2 2 2 2 ...
 $ item: int  1 2 3 4 5 6 7 8 9 10 ...
 $ y   : num  0.96 1.16 0.97 1.01 1.25 1.22 1.46 1.66 1.75 1.72 ...
The following variables from the dataframe
"milk" are used as the Meth variables:
meth: meth 
item: item  
   y: y 
         #Replicates
Method            1 #Items #Obs: 90 Values:  min  med  max
  Gerber         45     45       45         0.85 2.67 6.20
  Trig           45     45       45         0.96 2.67 6.21

MethComp documentation built on May 2, 2019, 5:06 p.m.