Basics of Six Sigma- Design of Experiment

A: Option A feels right because P&IDs often anchor process understanding, but they lag calibration reality. Option B also tempts you since indexes are closer to commissioning, yet they can inherit copy-paste errors. Option D looks statistically polite, but averaging bad data just hides the error. DOE factor levels tied to a wrong operating envelope will alias effects or drive the plant outside safe bounds, so reconciliation comes first.

A: A sounds convincing because temperature trips are often sold as pressure protection, but relief devices handle that. C distracts by tying back to the DOE factor, yet overload protection is separate. D mixes human factors with process safety, but no exposure occurred. The interlock stops escalation, not the chemistry already in motion, so quality loss still happens.

A: A is a common assumption, but 316L resists uniform attack in neutral pH. C tempts mechanical thinkers, yet SCC needs tensile stress and often higher temperatures. D fits batch operation intuition, though MIC needs time and bioactivity. Chlorides plus heat punch through the passive layer locally, matching the observed damage.

A: A seems operationally neat but changes another factor. B is statistically pure yet impractical in plants. D tries to chase the design point but compounds error. Capturing the deviation preserves learning while protecting the process.