0 - 3 of 3 tags for cpu skew

How is session level CPU and IO skew calculated as dispalyed in Viewpoint for a particular session (in Query Monition) in the "Skew" tab for a particular session?Is it the skew factor of the currently executing query of the session.There are top 3 and bottom 3 Amp (along with Amp#)  and their corresponding CPU and IO consumption values.Is there any relati

In Viewpoint Query-Monitor, for a particular session we can check the cpu skew and also the highest and average cpu.
If I want to check this from database, then which table and column shall I refer, is it DBQLogTbl or AMPUsageV view or anything else?

Can anyone please provide some clue about the reason for the following performance issues.