ROC curves of NPCPS and other methods when inappropriate formula applied.

<p>(A) Over expression formula applied to simulated under expressed gene, <i>n</i>₁ = <i>n</i>₂ = 25, μ = −2, <i>k</i> = 8. (B) Under expression formula applied to simulated over expressed gene, <i>n</i>₁ = <i>n</i>₂ = 25, μ = 2, <i>k</i> = 8. The x-axis is FPR, and the y-axis is TPR. ▽ is T, × is COPA, ○ is OS, • is ORT, ◊ is MOST, dotted line is LRS, dashed line is PPST, and solid line is NPCPS. The significance level α = 0.01 for NPCPS. NPCPS maintained the same level of sensitivity when applied to both types of simulated over-expressions. The other methods were not able to give results as good as when appropriate functions were applied as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020060#pone-0020060-g002" target="_blank">Fig. 2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0020060#pone-0020060-g003" target="_blank">Fig. 3</a>.