# R - Standard Deviation

The R sd() function returns standard deviation of all elements present in the argument. The syntax for using this function is given below:

### Syntax

```sd(x, na.rm = FALSE)
```

### Parameters

 `x` `Required. `Specify numeric vector. `na.rm` `Optional. `Specify TRUE to remove NA or NaN values before the computation. Default is FALSE.

### Return Value

Returns standard deviation of all elements present in the argument.

### Example:

The example below shows the usage of sd() function.

```vec <- c(10, 55, 25, -56, 30, 99)
cat("Standard deviation of all elements of vec:", sd(vec), "\n")

mat <- matrix(c(10, 55, 25, -56, 30, 99), ncol=2)
cat("\nThe matrix contains:\n")
print(mat)
cat("Standard deviation of all elements of mat:", sd(mat))
cat("\nStandard deviation of elements along first column:", sd(mat[,1]))
```

The output of the above code will be:

```Standard deviation of all elements of vec: 51.30075

The matrix contains:
[,1] [,2]
[1,]   10  -56
[2,]   55   30
[3,]   25   99
Standard deviation of all elements of mat: 51.30075
Standard deviation of elements along first column: 22.91288
```

## Using na.rm parameter

The na.rm parameter can be set TRUE to remove NA or NaN values before the computation.

### Example:

Consider the example below to see the usage of na.rm parameter.

```v1 <- c(10, 55, 25, -56, 30, 99, NA)
v2 <- c(10, 55, 25, -56, 30, 99, NaN)

cat("Standard deviation of all elements of v1:", sd(v1), "\n")
cat("Standard deviation after removing NA:", sd(v1, na.rm=TRUE), "\n")

cat("\nStandard deviation of all elements of v2:", sd(v2), "\n")
cat("Standard deviation after removing NaN:", sd(v2, na.rm=TRUE), "\n")
```

The output of the above code will be:

```Standard deviation of all elements of v1: NA
Standard deviation after removing NA: 51.30075

Standard deviation of all elements of v2: NA
Standard deviation after removing NaN: 51.30075
```

❮ R Statistical Functions

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