# Z Score

# 1 General

**Type:**- Matrix Processing**Heading:**- Normalization**Source code:**ZScore.cs

# 2 Brief description

The mean of each row/column is subtracted from each value. The result is then divided by the standard deviation of the row/column.

Output: Normalized expression matrix.

# 3 Parameters

## 3.1 Matrix access

Specifies whether the z-scoring is performed on rows or columns (default: Rows).

### 3.1.1 Grouping

This parameter is just relevant, if the “Matrix access” is set to “Rows”. It specifies, whether the normalization should be applied separately on groups (default:

## 3.2 Use median

If checked, the median and not the mean of each row/column is used for the calculation of the z-score of each matrix cell (default: unchecked).

## 3.3 Report mean and std. dev.

If checked, the mean and the standard deviation used for the calculation are reported (default: unchecked). In case the z-scoring is based on rows (“Matrix access” = “Rows”), the calculated mean and standard deviation appear in 2 newly generated numeric columns called “Mean” and “Std. dev.” containing the mean and standard deviation of each row. In case the calculation is based on columns (“Matrix access” = “Columns”), 2 new numeric rows are generated containing the mean and standard deviation of each column.