You may know the Apdex (Application Performance Index) to give a meaningful statement about an application's performance.
There are these three satisfaction zones, namely "satisfied", "tolerated" and "frustrated" with the corresponding thresholds T1 that separates the satisfied and tolerated zones and T2 that separates the tolerated and frustrated zones. Now, the Apdex formula says T2 = 4*T1
My question: Where does this factor 4 times come from?
Has anyone an idea?