colVars: Column variances
In asuR: Advanced statistics using R

Description Usage Arguments Value Author(s) See Also Examples

Form column variances for numeric arrays

1	colVars(x, na.rm = FALSE, dims = 1, unbiased = TRUE, SumSquares = FALSE, twopass = FALSE)

`x`	A numeric array (or a dataframe to convert to a matrix)
`na.rm`	Logical: Remove NA's (not available values)
`dims`	Number of dimensions to sum over [colSums] or leave alone [rowSums]. Only useful when x is a multidimensional array
`unbiased`	Logical: Use (N-1) in the denominator when calculating variance
`SumSquares`	Logical: If TRUE, colVars just returns sums of squares.
`twopass`	Logical: If TRUE, colVars uses the corrected two-pass algorithm of Chan Golub & LeVeque, which is slower but less subject to roundoff error.

A vector with the variance for every column.

colVars: Originally by Douglas Bates <bates@stat.wisc.edu> as package "MatUtils". Modified, expanded, and renamed by David Brahm <brahm@alum.mit.edu>, with help of course from the R-help gurus.

colMeans

mat <- cbind(rnorm(100, sd=sqrt(1)),
             rnorm(100, sd=sqrt(2)),
             rnorm(100, sd=sqrt(3)),
             rnorm(100, sd=sqrt(4)),
             rnorm(100, sd=sqrt(5)))
colVars(mat)