# sample.Meth: Sample Meth object with replacement In MethComp: Analysis of Agreement in Method Comparison Studies

## Description

Sample a `Meth` object with replacement. If `how=="random"`, a random sample of the rows are sampled, the existing values of `meth`, `item` and `y` are kept but new replicate numbers are generated. If `how=="linked"`, a random sample of the linked observations (i.e. observations with identical `item` and `repl` values) are sampled with replacement and replicate numbers are kept. If `how=="item"`, items are sampled with replacement, and their observations are included the sampled numner of times.

## Usage

 ```1 2 3 4 5``` ```sample.Meth( x, how = "random", N = if (how == "items") nlevels(x\$item) else nrow(x) ) ```

## Arguments

 `x` A `Meth` object. `how` Character. What sampling strategy should be used, one of `"random"`, `"linked"` or `"item"`. Only the first letter is significant. See details for explanation. `N` How many observations should be sampled?

A meth object

## Author(s)

Bendix Carstensen, bendix.carstensen@regionh.dk

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32``` ```data(fat) # Different ways of selecting columns and generating replicate numbers Sub1 <- Meth(fat,meth=2,item=1,repl=3,y=4,print=TRUE) Sub2 <- Meth(fat,2,1,3,4,print=TRUE) Sub3 <- Meth(fat,meth="Obs",item="Id",repl="Rep",y="Sub",print=TRUE) summary( Sub3 ) plot( Sub3 ) # Use observation in different columns as methods data( CardOutput ) head( CardOutput ) sv <- Meth( CardOutput, y=c("Svo2","Scvo2") ) # Note that replicates are generated if a non-unique item-id is used sv <- Meth( CardOutput, y=c("Svo2","Scvo2"), item="Age" ) str( sv ) # A summary is not created if the the first argument (data=) is not used: sv <- Meth( y=CardOutput[,c("Svo2","Scvo2")], item=CardOutput\$VO2 ) summary(sv) # Sample items ssv <- sample.Meth( sv, how="item", N=8 ) # More than two methods data( sbp ) plot( Meth( sbp ) ) # Creating non-unique replicate numbers per (meth,item) creates a warning: data( hba1c ) hb1 <- with( hba1c, Meth( meth=dev, item=item, repl=d.ana-d.samp, y=y, print=TRUE ) ) hb2 <- with( subset(hba1c,type=="Cap"), Meth( meth=dev, item=item, repl=d.ana-d.samp, y=y, print=TRUE ) ) ```

MethComp documentation built on Jan. 20, 2020, 1:12 a.m.