Statistical functions take the R vector as an input besides the arguments and give the result. R has many inbuilt statistical functions, and **mean() **is one of them. The **mean** of an observation variable is a numerical measure of the prime location of the data values. Mean is the sum of its data values divided by data count.

**Mean in R**

The mean is calculated by taking a sum of the values and dividing by the number of values in the data. If the data series is a vector, then the mean is calculated by taking a sum of vector elements and dividing by the number of elements of the series.

To calculate the mean in R, use an inbuilt mean() function.

**Syntax**

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

**Parameters**

The **x** is an input vector.

The **trim** is used to drop some observations from both ends of the sorted vector.

The **na.rm** is used to remove the missing values from the input vector.

**Example**

```
# Create a vector.
rv <- c(11, 18, 19, 21, 29, 46)
# Find Mean of rv vector.
meanResult <- mean(rv)
print(meanResult)
```

**Output**

```
[1] 24
```

That means the sum of all the vector elements is 144, and 144 / 6 is 24.

**Passing trim option**

The mean() function optionally takes the **trim **parameter. When you pass the trim parameters, the values in the vector get sorted, and then the required numbers of observations are dropped from calculating the mean.

If you pass the **0.3, **3 values from each end will be dropped from the calculations to find the mean.

```
# Create a vector.
rv <- c(11, 18, 19, 21, 29, 46)
# Find Mean of rv vector.
meanResult <- mean(rv, trim = 0.3)
print(meanResult)
```

**Output**

`[1] 21.75`

**Passing NA Option**

If there are missing values, then the mean() function returns **NA**.

```
# Create a vector.
rv <- c(11, 18, 19, NA, 29, 46)
# Find Mean of rv vector.
meanResult <- mean(rv)
print(meanResult)
```

**Output**

`[1] NA`

To drop the missing values from the calculation, use **na.rm = TRUE**. Which means remove the **NA** values.

```
# Create a vector.
rv <- c(11, 18, 19, NA, 29, 46)
# Find Mean of rv vector.
meanResult <- mean(rv, na.rm = TRUE)
print(meanResult)
```

**Output**

`[1] 24.6`

**Conclusion**

R mean() is an inbuilt function that calculates the arithmetic mean. The mean() function takes optional parameters that you can use according to your needs.