Which statement is true about interval data?

• A. Differences between values can be measured
• B. Contains a true zero
• C. Ratios are meaningful
• D. Data consist of categories with no order

Answer: (A)

Interval data are numeric scales with equal spacing between values and an arbitrary zero point, which allows you to measure the size of differences between values. Because the zero is not a true absence of the quantity, ratios aren’t meaningful (for example, 30°C isn’t twice 15°C). These data are ordered and numeric, not categorical, so you can compute differences and other arithmetic on them, but you cannot rely on meaningful ratios or interpret zero as a true zero. This is why the statement that differences between values can be measured is the correct characterization of interval data.