ave {stats} R Documentation

## Group Averages Over Level Combinations of Factors

### Description

Subsets of `x[]` are averaged, where each subset consist of those observations with the same factor levels.

### Usage

```ave(x, ..., FUN = mean)
```

### Arguments

 `x` A numeric. `...` Grouping variables, typically factors, all of the same `length` as `x`. `FUN` Function to apply for each factor level combination.

### Value

A numeric vector, say `y` of length `length(x)`. If `...` is `g1, g2`, e.g., `y[i]` is equal to `FUN(x[j]`, for all `j` with `g1[j] == g1[i]` and `g2[j] == g2[i])`.

`mean`, `median`.

### Examples

```require(graphics)

ave(1:3)  # no grouping -> grand mean

attach(warpbreaks)
ave(breaks, wool)
ave(breaks, tension)
ave(breaks, tension, FUN = function(x) mean(x, trim = 0.1))
plot(breaks, main =
"ave( Warpbreaks )  for   wool  x  tension  combinations")
lines(ave(breaks, wool, tension              ), type = "s", col = "blue")
lines(ave(breaks, wool, tension, FUN = median), type = "s", col = "green")
legend(40, 70, c("mean", "median"), lty = 1,
col = c("blue","green"), bg = "gray90")
detach()
```

[Package stats version 4.1.1 Index]