sample.Meth {MethComp} | R Documentation |
Sample Meth object with replacement
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
sample.Meth(
x,
how = "random",
N = if (how == "items") nlevels(x$item) else nrow(x)
)
Arguments
x |
A |
how |
Character. What sampling strategy should be used, one of
|
N |
How many observations should be sampled? |
Value
A meth object
Author(s)
Bendix Carstensen, bendix.carstensen@regionh.dk
Examples
data(fat)
# Different ways of selecting columns and generating replicate numbers
Sub1 <- Meth(fat,meth=2,item=1,repl=3,y=4,print=TRUE)
Sub2 <- Meth(fat,2,1,3,4,print=TRUE)
Sub3 <- Meth(fat,meth="Obs",item="Id",repl="Rep",y="Sub",print=TRUE)
summary( Sub3 )
plot( Sub3 )
# Use observation in different columns as methods
data( CardOutput )
head( CardOutput )
sv <- Meth( CardOutput, y=c("Svo2","Scvo2") )
# Note that replicates are generated if a non-unique item-id is used
sv <- Meth( CardOutput, y=c("Svo2","Scvo2"), item="Age" )
str( sv )
# A summary is not created if the the first argument (data=) is not used:
sv <- Meth( y=CardOutput[,c("Svo2","Scvo2")], item=CardOutput$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 ) )