# How to Use Mean() In R with Examples

This tutorial shows how to use the function of mean() in R with examples.

In particular, mean() can be used to calculate mean in R. The following is the basic statement.

mean(x, trim = 0, na.rm = FALSE)

• x: It is an R object.
• trim: It is in the range of (0 to 0.5). The number indicates the percentage of observations to be trimmed from each end of sorted `x`, before the mean is computed. The default value is 0.
• na.rm: It is a logical value indicating whether `NA` values should be stripped before the computation proceeds. The default value is FALSE.

## Example 1: Basic format

``````x <- c(4,5,8,44,32,22,45,3,8,99,100,120)
mean(x)``````

Output:

```> x <- c(4,5,8,44,32,22,45,3,8,99,100,120)
> mean(x)
 40.83333```

## Example 2: With trim

Example 2 shows how to use `trim` in mean(). trim will remove the percentage of observations on both ends in the sorted vector.

``````x <- c(4,5,8,44,32,22,45,3,8,99,100,120)
mean(x, trim=0.1)``````

Output:

```> x <- c(4,5,8,44,32,22,45,3,8,99,100,120)
> mean(x, trim=0.1)
 36.7```

We can sort the vector and remove both end to see whether we can get the exactly same result.

``````# create a vector in R
x <- c(4,5,8,44,32,22,45,3,8,99,100,120)

# sort the vector
sort(x, decreasing = FALSE)

# calculate the number of the observations
print(length(x))

# calculate the number of observations we need to remove on both ends
print(length(x)*0.1)``````

Output:

```> sort(x, decreasing = FALSE)
   3   4   5   8   8  22  32  44  45  99 100 120

> length(x)
 12

> 12*0.1
 1.2
```

Based on the output above, we know that we need to remove 1 observations (1.2 ≈ 1). Based on the sorted vector, we know that we need to remove 3 and 120 from both ends. Thus, we can manually calculate the mean to see whether we get the same mean of 36.7 shown above.

``````# manually calculate the mean
(sum(x)-3-120)/10``````

Output:

```> (sum(x)-3-120)/10
 36.7```

## Example 3: with NA

The following vector has `NA` in the vector. We can see that the `NA` will make the mean as `NA`.

``````x <- c(4,5,8,44,32,22,45,3,8,99,100,120,NA)
mean(x)
``````

Output:

```> x <- c(4,5,8,44,32,22,45,3,8,99,100,120,NA)
> mean(x)
 NA```
``````
# create a vector in R
x <- c(4,5,8,44,32,22,45,3,8,99,100,120,NA)

```> x <- c(4,5,8,44,32,22,45,3,8,99,100,120,NA)