A blue horizontal line shows the 0.05 significance level. Note that you can change this level by double-clicking the y-axis, removing the current reference line, and adding a new reference line.

A red increasing line provides an FDR threshold for unadjusted p-values. A p-value falls below the red line precisely when the FDR-adjusted p-value falls below the blue line. This enables you to read significance relative to the FDR from either the adjusted or unadjusted p-values.

FDR PValue Plot shows the FDR PValue Plot for the Probe.jmp sample data table. Note that some tests are significant according to the usual p-value but not according to the FDR p-value.