The questionable claim
A course survey includes only learners who finished and claims all learners found the course easy.
Investigate
Identify the unit of analysis, denominator, population or information boundary. What extra evidence would be needed? Write a corrected statement first.
Diagnosis and repair
The sample excludes people who stopped. State response/completion selection, seek feedback from non-completers where appropriate, and avoid generalizing satisfaction to all starters.
Prevention
Add a test or review question that catches the error before publication. Save the original and corrected explanation so your reasoning is auditable.
Try the activity before reading its reference. Keep your sources, commands and assumptions with your work. Companion activities are unsaved self-practice and do not award a certificate or change lesson progress.