Output Graphics and Action Buttons | Expression | MA Plots (Loess Normalization)

MA Plots (Loess Normalization)
The MA Plots tab is shown below:
The MA Plots tab contains the following elements:
These plots are used to show whether normalization should be carried out prior to data analysis. In the example shown here, a pair of plots is generated for each column; plots on the left and right were generated before and after normalization, respectively. The red spline indicates the mean differences in expression .
A standard assumption in microarray experiments is that few genes should exhibit a change in expression, meaning that most points on the y axis should be close to zero (0) and the spline should be relatively flat. The observed deviation in the splines in the raw data ( left plots) was significantly reduced by the normalization performed here.
See MA Plot for more details about these plots.