# sem {#sem}

**Parent topic:**[Functions](../../Functions/category.md)

## Syntax {#syntax}

`sem(X)`

## Arguments {#arguments}

**X** is a numeric vector/matrix/table.

## Details {#details}

Return unbiased \(normalized by N-1\) standard error of the mean over *X* .

-   If *X* is a matrix, calculate the standard error for each column and return a vector.

-   If *X* is a table, calculate the standard error of each column and return a table.


## Examples {#examples}

```
[1,4,9,10,20,32].sem();
// output: 4.688046

[1,4,9,10,NULL,20,32].sem();
// output: 4.688046
```

