Volcano Plot
Revision as of 15:42, 10 June 2011 by Smith (talk | contribs) (Created page with "{{TutorialsTopNav}} Image:Volcano_plot.png The Volcano Plot visualizer graphs the log2 fold change for each marker against the -log10 of the P-value. It is only availab...")
The Volcano Plot visualizer graphs the log2 fold change for each marker against the -log10 of the P-value.
It is only available when a t-test result is selected in the Project Folders component.
Fold Change - The fold change is calculated, for each marker, as the average expression in the Case set divided by the average expression in the control set. If the data is known to already be log2 transformed, the antilog of each value is first taken before averaging. The log2 of the ratio is then taken for use in the display.
Color scheme - the lower 2/3 of the absolute values of the (fold change) * (significance) are colored in shades from light blue (lowest values) to dark blue (highest values). The highest 1/3 of such values are colored from dark blue (lowest values) to red (highest values).
Export Data - The data depicted in the volcano plot is exported to a CSV format file. The column headers are: Probe Set Name, Gene Name, p-Value, Fold Change.
