Investigation types

Task goals

• Name and describe each of the four investigation types (summary, comparison, relationship, time-series).
• Classify a given research scenario or statistical question by its investigation type, and justify the classification.
• Match each investigation type to the graph or display best suited to it (single-variable display for summary, box-and-whisker/side-by-side for comparison, scatter plot for relationship, line/time-series graph for time-series).
• Classify a given variable as qualitative or quantitative, and as discrete or continuous, explaining the reasoning (including edge cases like ordinal rating scales or measurements rounded to whole numbers).
• Classify a data source as primary or secondary, and explain the trade-offs of using secondary data (convenience and cost vs fit and reliability).
• Recognise that a real investigation can combine more than one type (e.g. tracking two groups over time combines time-series and comparison), and explain why choosing the wrong investigation type or display can mislead.