matrixStats (version 0.12.2)

rowVars: Variance estimates for each row (column) in a matrix

Description

Variance estimates for each row (column) in a matrix.

Usage

rowVars(x, na.rm=TRUE, center=NULL, dim.=dim(x), ...)
 colVars(x, na.rm=TRUE, center=NULL, dim.=dim(x), ...)

Arguments

x

A numeric NxK matrix.

center

(optional) The center, defaults to the row means.

na.rm

If TRUE, NAs are excluded first, otherwise not.

dim.

An integer vector of length two specifying the dimension of x, also when not a matr

...

Additional arguments passed to rowMeans() and rowSums().

Value

• Returns a numeric vector of length N (K).

See Also

See rowMeans() and rowSums() in colSums().

Examples

set.seed(1)

x <- matrix(rnorm(20), nrow=5, ncol=4)
print(x)

# Row averages
print(rowMeans(x))
print(rowMedians(x))

# Column averages
print(colMeans(x))
print(colMedians(x))


# Row variabilities
print(rowVars(x))
print(rowSds(x))
print(rowMads(x))
print(rowIQRs(x))

# Column variabilities
print(rowVars(x))
print(colSds(x))
print(colMads(x))
print(colIQRs(x))


# Row ranges
print(rowRanges(x))
print(cbind(rowMins(x), rowMaxs(x)))
print(cbind(rowOrderStats(x, 1), rowOrderStats(x, ncol(x))))

# Column ranges
print(colRanges(x))
print(cbind(colMins(x), colMaxs(x)))
print(cbind(colOrderStats(x, 1), colOrderStats(x, nrow(x))))


x <- matrix(rnorm(2400), nrow=50, ncol=40)

# Row standard deviations
d <- rowDiffs(x)
s1 <- rowSds(d)/sqrt(2)
s2 <- rowSds(x)
print(summary(s1-s2))

# Column standard deviations
d <- colDiffs(x)
s1 <- colSds(d)/sqrt(2)
s2 <- colSds(x)
print(summary(s1-s2))