It is so intense and deep, they ask questions related to your course and so simple if you know it, but if you don't know it, it is so difficult

You've got to pass an aptitude test and a test on statistics and six sigma/lean to get to the interview. You get to interview with the COO and Six Sigma manager. Pretty intense. Mostly behavioural questions. They also want to guage your loyalty/commitment. The position has a high turnover rate.