New PMP Question & Answers with explanation

Caitlin’s project is behind schedule. She is planning to crash the project by allowing overtime to the project team. This approach can bring additional risks to the project. Which of the following is not a valid risk in this scenario:
Select one
Cause-and-Effect diagrams are used to illustrate how various factors might link to potential problems or effects. They are also called:
Select one
You are the project manager managing a project to design a print head for dot matrix printers. In order to determine ideal settings for print quality, the quality manager of the company suggests trying out various scenarios for printing by varying certain parameters on the print head. Identifying such variables which influence the product or process under development is called:
Select one
The Plan-Do-Check-Act (PDCA) cycle as the basis for quality improvement is usually attributed to:
Select one
A control chart is used to determine whether a process is stable or has predictable performance. When a process is within acceptable limits, the process does not need adjustment. How are these upper and lower control limits determined?
Select one