ave
Group Averages Over Level Combinations of Factors

### Description

Computes group averages or applies other specified function on groups of data that have same factors.

### Usage

    ave(x, ..., FUN = mean, drop = TRUE)

### Arguments

x | a numeric vector
... | a list of factors, all of them have the same length as x. It can be empty.
FUN | a function applied for each group of factor level combination. Default is mean.
drop | a logical scalar passed to interaction. It is only here so that R users don't run into an error (in R 2.15.1 drop=TRUE was required to avoid unnecessarily calling FUN on zero-length arguments.

### Details

All factors in ... will be combined in one factor via function interaction(), and then FUN is applied for each group of factor level combination.
Value
a numeric vector with the same length as x. Its elements are the result of FUN applied for each group of factor level combination.
See Also
mean, interaction
Examples

    scores <- c(78, 80, 67, 95, 85, 89, 76, 94, 69, 82, 85, 77)
    genders <- factor(c("F", "M", "M", "M", "F", "F", "F", "M", "F", "F", "M", "M"))
    ages <- factor(c("Low", "Mid", "High", "High", "Mid", "Mid", "Low", "Low", "Mid", "Mid", "Mid", "High"))
    ave(scores, ages) # no FUN: means by age group
    ave(scores, ages, FUN = median) # medians by age group
    ave(scores, genders, ages) # same as fitted(lm(scores ~ genders * ages))
    ave(scores)  # no group, no FUN: grand mean

Package stats version 6.1.5-18
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