Hmisc (version 3.0-10)

xy.group: Mean x vs. function of y in groups of x

Description

Compute mean x vs. a function of y (e.g. median) by quantile groups of x or by x grouped to have a given average number of observations. Deletes NAs in x and y before doing computations.

Usage

xy.group(x, y, m=150, g, fun=mean, result="list")

Arguments

x

a vector, may contain NAs

y

a vector of same length as x, may contain NAs

m

number of observations per group

g

number of quantile groups

fun

function of y such as median or mean (the default)

result

"list" (the default), or "matrix"

Value

• if result="list", a list with components x and y suitable for plotting. if result="matrix", matrix with rows corresponding to x-groups and columns named n, x, and y.

concept

• grouping
• stratification
• aggregation
• discretization

See Also

cut2, tapply

Examples

# plot(xy.group(x, y, g=10))	#Plot mean y by deciles of x
# xy.group(x, y, m=100, result="matrix")	#Print table, 100 obs/group