New PMP Question & Answers with explanation

During an inspection of a project deliverable, the team detects the same defect in the deliverable that has already been identified during a previous inspection. The project manager is confused how this could have happened since a change request was approved to correct the defect. After discussing the issue with the team, the project manager learns that the team never implemented the approved change request. What could have helped prevent this situation?
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You are managing an engineering design project. The vendor has created 50 engineering drawings. Since the project is on a tight schedule and budget, checking every drawing for accuracy and completeness would be impossible. You direct the team to randomly select 20 drawings for inspection. This exercise can best be described as an example of:
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Which of the following helps a project manager determine possible causes of potential problems and actual problems?
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A project manager has to resolve two problems. Both problems can occur in a single trial. In this situation, what is the best action the project manager can take?
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You are the program level manager with several project activities underway. In the executing process group, you begin to become concerned about the accuracy of progress reports from the projects. What would best support your opinion that there is a problem?
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