# Missing values

## Missing and excluded cells or values for statistical analysis

The following cells and values are excluded for statistical analysis:

**Empty cells****Cells that cause a computational error****User-defined missing values****Excluded values**

## Empty cells

The data for all variables of a particular case (patient, sample) are entered on one row in the spreadsheet. When for one variable you do not know the value (or entry) for the case, you leave the corresponding cell blank and do not enter any data in this cell.

## Cells that cause a computational error

As a rule, the program will ignore an entry for a numeric variable when it is unable to interpret this entry as a number.

When text is entered in a cell for a numeric variable, the program will not take this case into account for calculations (it will not substitute the text value by a zero).

The following are not recognized as numbers and are ignored for calculations:

5,8 (when the decimal symbol is not a comma)

'4.6

LOG(CONC) (when 'Conc' is not a correctly defined variable or in case the variable 'Conc' has a zero, negative or missing value)

SQRT(-9) (error!)

1/LENGTH (when 'Length' is not a correctly defined variable or in case 'Length' equals zero)

## User-defined missing values

User-defined missing values van be entered on the **Missing values** tab of the File properties dialog box. These values are ignored for calculations.

## Excluded values

You may exclude particular cells or rows using the Exclude command. This in particular is useful for excluding outliers.