# Documentation/How Tos/Calc: DVAR function

## Contents

## DVAR

Returns the bias-corrected sample variance of values in a column of a Calc 'database' table, in rows which meet specified criteria.

### Syntax:

**DVAR(database_table; field; criteria_table)**

where

is a range defining the data to be examined.**database_table**

is the column to examine. It may be a column number (1 is the first column of the database table, 2 is the second ...) or a column header (enclosed in quotation marks ””) or a cell referring to a column header.**field**

is a range containing criteria, which are used to select which rows of the**criteria_table**to examine.**database_table**

- The Database functions overview describes these parameters in detail.

` DVAR` returns the

**bias-corrected sample variance**, which assumes that the chosen rows of the

`contain a random sample of a normally distributed population. If the chosen data are the entire population, use`

**database_table****instead. The**

`* DVARP``calculation uses this formula:`

**DVAR**where N is the number of values included and x_{i} are those values.

` DVAR` ignores any cell containing text in the

`column.`

**field**

Simply put, variance is a measure of how widely spread data values are. It is the square of the *standard deviation* (see ** * DSTDEV**,

**). Variance is a reliable measure only if there is enough data to examine.**

`* DSTDEVP`

### Example:

In this spreadsheet:

A |
B |
C |
D |
E
| |

1 |
Name | Grade | Age | Distance to School | Weight |

2 |
Andy | 3 | 9 | 150 | 40 |

3 |
Betty | 4 | 10 | 1000 | 42 |

4 |
Charles | 3 | 10 | 300 | 51 |

5 |
Daniel | 5 | 11 | 1200 | 48 |

6 |
Eva | 2 | 8 | 650 | 33 |

7 |
Frank | 2 | 7 | 300 | 42 |

8 |
Greta | 1 | 7 | 200 | 36 |

9 |
Harry | 3 | 9 | 1200 | 44 |

10 |
Irene | 2 | 8 | 1000 | 42 |

11 |
|||||

12 |
|||||

13 |
Name | Grade | Age | Distance to School | Weight |

14 |
2 |

**DVAR(A1:E10; "Weight"; A13:E14)**

- returns the bias-corrected sample variance of the weights of children in the second grade. This is not a useful measure, as there are so few children.

### Issues:

- The OOo2.3 Help implies that
as a**0**will include the entire database table. This seems to be wrong - only the variance of a single column can be found.**field**

- Logical values TRUE and FALSE are interpreted as 1 and 0 in the calculation. This is not compatible with Excel, which ignores logical values. This will very rarely cause difficulty.

**See Also**