Nest: A function to calculate the N individuals/groups required to...
In ICC: Functions facilitating the estimation of the Intraclass Correlation Coefficient

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/Nest.r

Given a predicted ICC and k measures per individual/group, this function will calculate the N individuals/groups required to obtain a desired confidence interval w(according to Bonett, 2002).

1 2	Nest(est.type = c("hypothetical", "pilot"), w, ICC = NULL, k = NULL, x = NULL, y = NULL, data = NULL, alpha = 0.05)

`est.type`	character string of either `"hypothetical"` indicating usage of the given values of `k` and `ICC` or if `"pilot"` is specified then to calculate these from the dataset provided. Also, just the first letter may be used
`w`	desired width of the confidence interval about the ICC estimate
`ICC`	expected intraclass correlation coefficient
`k`	number of measurements per individual or group
`x`	column name of `data` indicating the individual or group ID from a pilot study
`y`	column name of `data` indicating the measurements from a pilot study
`data`	a `data.frame` from a pilot experiment
`alpha`	the alpha level to use when estimating the confidence interval

More than one ICC or k may be given. In this case, the return value is a dataframe with rows representing the values of the specified ICCs and the columns yield the different k values.

data.frame indicating the N number of individuals or groups to use to estimate the given ICC with a desired confidence interval width. Rows represent different levels of ICC while columns indicate different levels of k measurements per individual/group.

Matthew Wolak matthewwolak@gmail.com

D.G. Bonett. 2002. Statistics in Medicine, 21(9): 1331-1335.

M.E. Wolak, D.J. Fairbairn, Y.R. Paulsen. 2011. Methods in Ecology and Evolution.

ICCest

#Example 1
n1<-Nest("h", w=0.14, ICC=0.1, k=10)
n1

#Example 2
data(ChickWeight)
Nest("p", w=0.14, x=Chick, y=weight, data=ChickWeight)
ex2<-ICCest(Chick, weight, ChickWeight)
ex2$UpperCI-ex2$LowerCI #confidence interval width of pilot study
ex2

#Example 3
Nest("h", w=0.14, ICC=seq(0.05, 0.15, 0.05), k=seq(10,12,1))