- id: preview-output
  question: "What does `head(activity, 3)` return in this lesson?"
  answers:
    - text: "The first three rows of the activity data."
      correct: true
    - text: "A grouped summary by program."
      correct: false
    - text: "A scatterplot of study hours and quiz score."
      correct: false
  tags:
    - data-import
    - "Recognize the output of head(activity, 3)"
  difficulty: introductory
  language: en
  explanation: "`head(activity, 3)` previews the first three rows, which helps students inspect the data structure before analysis."

- id: grouped-summary
  question: "After grouping by `program`, what does `mean_hours` represent?"
  answers:
    - text: "The average study hours within each academic program."
      correct: true
    - text: "The total study hours across all students."
      correct: false
    - text: "The quiz score for the first student in each program."
      correct: false
  tags:
    - summarisation
    - dplyr
    - "Compute mean study hours and mean quiz score"
  difficulty: introductory
  language: en
  explanation: "The `summarise()` call computes an average separately within each `program` group."

- id: visualization-aesthetic
  question: "In `ggplot2`, which aesthetic should be mapped to show quiz score on the vertical axis?"
  answers:
    - text: "y"
      correct: true
    - text: "x"
      correct: false
    - text: "color"
      correct: false
  tags:
    - visualization
    - ggplot2
  difficulty: introductory
  language: en
  explanation: "The y aesthetic controls the vertical position in a two-dimensional plot."

- id: plot-interpretation
  question: "Which interpretation is appropriate for the scatterplot in this synthetic example?"
  answers:
    - text: "Students with more study hours tend to have higher quiz scores in this small dataset, but the plot is not causal evidence."
      correct: true
    - text: "The plot proves that increasing study hours causes higher quiz scores."
      correct: false
    - text: "The plot shows that all programs have identical quiz scores."
      correct: false
  tags:
    - visualization
    - interpretation
    - "Map study_hours to x and quiz_score to y"
  difficulty: introductory
  language: en
  explanation: "The plot supports a cautious descriptive statement only; the data are synthetic and not designed for causal inference."
