PK0-005 Tools and Documentation Practice Question
In a manufacturing project, the team uses a Pareto chart to analyze defects. The chart shows that 80% of defects come from 20% of the causes. Which principle does this illustrate?
⚠ Common exam trap
PK0-005 often tests the confusion between Pareto (80/20 prioritization) and Fishbone (cause categorization) — candidates pick Fishbone because both are quality tools used in root-cause analysis.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
80/20 rule
The Pareto chart visualizes the Pareto principle, also known as the 80/20 rule, which states that roughly 80% of effects come from 20% of causes. In quality management, this helps teams focus on the vital few defect sources that produce the majority of problems, rather than spreading effort across trivial many causes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Scatter diagram
Why it's wrong here
A scatter diagram plots two variables to reveal correlation, not the frequency ranking of defect causes. It is tempting because both are quality tools, and a scatter diagram would be correct when testing whether one measurable factor relates to another, such as temperature versus defect rate.
- ✓
80/20 rule
Why this is correct
The 80/20 rule, or Pareto principle, states that a minority of causes produces a majority of effects. The chart's finding that 20% of causes generate 80% of defects is precisely this principle, which is why the Pareto chart is named after it.
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Control limits
Why it's wrong here
Control limits define statistical process control boundaries for variation, not the 80/20 distribution of defect causes. They are tempting because both appear in quality management, and control limits would be correct when determining whether a process is stable or detecting out-of-control variation.
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Fishbone diagram
Why it's wrong here
A fishbone diagram maps cause categories to an effect; it does not quantify defect frequency or rank causes. It is tempting because both tools support root-cause analysis, and a fishbone would be correct when the team needs to brainstorm and structure potential causes rather than prioritise them.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This PK0-005 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PK0-005 exam.