PMI CAPM (Certified Associate in Project Management) Examination Content OutlineQuality Management and Continuous Process ImprovementHard
A project manager is establishing a quality control process for a highly complex engineering project. They need to define the acceptable range of variation for critical component specifications. Which statistical technique is primarily used to set these upper and lower control limits?
- AANOVA
- BStatistical Sampling
- CStandard Deviation
- DRegression Analysis
Show answer & explanationAnswer & explanation
Correct answer: C. Standard Deviation
Standard deviation is a measure of the amount of variation or dispersion of a set of values. In quality control, control limits (typically ±3 standard deviations from the mean) are calculated using standard deviation to define the acceptable range of variation for a process. Values outside these limits indicate the process is out of control.
Why the other options are wrong
- A. ANOVA (Analysis of Variance) compares means of three or more groups, not directly used for setting control limits.
- B. Statistical Sampling is a method of selecting a subset of a population for inspection, not a technique for calculating control limits.
- D. Regression Analysis models the relationship between a dependent variable and one or more independent variables, not for setting control limits.
Standard Deviation in Quality Control
A statistical measure that quantifies the amount of variation or dispersion of a set of data values around the mean, used to set control limits.
- The basis for calculating control limits (e.g., ±3 standard deviations).
- Higher standard deviation indicates more variation.
- Crucial for determining if a process is 'in control'.
Memory trick: Control with Stats: Standard deviation sets the bounds, so the process stays in its grounds.