Explanation/Reference:
Explanation:
This technique is used to identify which variables have the most influence. It is a statistical method to identify the factors that may influence specific variables of a product or process under development or in production. For example, roller blade designers might want to determine which combination of number of wheels and titanium ball bearings would produce the most desirable "ride" characteristics at a reasonable cost. This technique, however, can be applied to project management issues such as cost and schedule trade-offs. An appropriately designed "experiment" often will help project managers to find an optimal solution from a relatively limited number of options, and often it help to determine the number and type of tests to use and their impact on quality.

According to the PMBOK Guide, a retrospective is a meeting held by a project team at the end of a project or process (often after an iteration) to discuss what was successful about the project or time period covered by that retrospective, what could be improved, and how to incorporate the successes and improvements into future iterations or projects. In an agile project, retrospectives are usually held at the end of each iteration or sprint, regardless of the size or duration of the increment, milestone, or progress. The purpose of retrospectives is to enable continuous improvement and learning throughout the project life cycle, not just at the end of a major phase or deliverable. Therefore, the project manager should organize the first team retrospective when the work is progressing well through the team, which implies that the team has completed at least one iteration or sprint and has some feedback to share and act upon. References: (Professional in Business Analysis Reference Materials source and documents)
* PMBOK Guide, 6th edition, Chapter 4, Section 4.6.1.2, page 123
* PMBOK Guide, 6th edition, Appendix X3, Section X3.2.2, page 718
* PMI PMP-Project Management Professional Practice Exam Q. 781 to 790