challenge: What is tampering in the context of a controlled process, as introduced by W. Edwards Deming?
  
  A. Ignoring control charts to increase production output
  B. Adjusting the process to optimize production speed
  C. Adjusting the process on the basis of outcomes which are outside the expected range of variability
  D. Adjusting the process on the basis of outcomes which are within the expected range of variability
  Answer: 