Module 6 Checkpoint: Probability, Randomness, and Variation
Scenario
A process fails about 5% of the time. In the last 20 runs there were three failures, and someone concludes the process is getting worse.
Questions
- How many failures would you expect in 20 runs?
- Is three failures surprising enough to conclude anything? Say why.
- What would make you take the claim more seriously?
- Explain in one sentence why a run of three failures can happen with no change in the process.
- What would you do next, and what would you not say yet?
Pass Standard
You pass when you can distinguish ordinary variation from a change in the process, and say what evidence would separate them.