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# stats::stdev

Standard deviation of a data sample

### Use only in the MuPAD Notebook Interface.

This functionality does not run in MATLAB.

## Syntax

```stats::stdev(x1, x2, …, <Sample | Population>)
stats::stdev([x1, x2, …], <Sample | Population>)
stats::stdev(s, <c>, <Sample | Population>)
```

## Description

stats::stdev( x1, x2, ..., xn) returns the standard deviation

,

where is the arithmetic mean of the data xi.

stats::stdev( x1, x2, ..., xn, Population) returns

.

The standard deviation is the square root of the variance.

The column index c is optional, if the data are given by a stats::sample object containing only one non-string column. Cf. Example 3.

External statistical data stored in an ASCII file can be imported into a MuPAD® session via import::readdata. In particular, see Example 1 of the corresponding help page.

## Examples

### Example 1

We calculate the standard deviation of three values:

`stats::stdev(2, 3, 5)`

Alternatively, the data may be passed as a list:

`stats::stdev([2, 3, 5])`

### Example 2

We create a sample:

`stats::sample([[a1, b1, c1], [a2, b2, c2]])`
```a1  b1  c1
a2  b2  c2
```

The standard deviation of the second column is:

`expand(stats::stdev(%, 2))`

### Example 3

We create a sample consisting of one string column and one non-string column:

`stats::sample([["1996", 1242], ["1997", 1353], ["1998", 1142]])`
```"1996"  1242
"1997"  1353
"1998"  1142
```

We compute the standard deviation of the second column. In this case this column does not have to be specified, since it is the only non-string column:

`float(stats::stdev(%))`

We repeat the computation with the option Population:

`float(stats::stdev(%2, Population))`

## Parameters

 x1, x2, … The statistical data: arithmetical expressions s A sample of domain type stats::sample c An integer representing a column index of the sample s. This column provides the data x1, x2 etc.

## Options

 Population, Sample With Sample, the data are regarded as a "sample", not as a full population. The default is Sample.

## Return Values

Arithmetical expression.