| contr.meandif {RoBMA} | R Documentation |
Mean difference contrast matrix
Description
Return a matrix of mean difference contrasts.
This is an adjustment to the contr.orthonormal that ascertains that the prior
distributions on difference between the gran mean and factor level are identical independent
of the number of factor levels (which does not hold for the orthonormal contrast). Furthermore,
the contrast is re-scaled so the specified prior distribution exactly corresponds to the prior
distribution on difference between each factor level and the grand mean – this is approximately
twice the scale of contr.orthonormal.
Usage
contr.meandif(n, contrasts = TRUE)
Arguments
n |
a vector of levels for a factor, or the number of levels |
contrasts |
logical indicating whether contrasts should be computed |
Value
A matrix with n rows and k columns, with k = n - 1 if contrasts = TRUE and k = n
if contrasts = FALSE.
References
There are no references for Rd macro \insertAllCites on this help page.
Examples
contr.meandif(c(1, 2))
contr.meandif(c(1, 2, 3))