matrixStats (version 0.1.5)

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

Description

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

Usage

rowVars(x, center=NULL, ...)
 colVars(x, ...)

Arguments

x

A numeric NxK matrix.

center

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

...

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))