Which of the following is an example of ratio data?

• A. Height in cm
• B. Temperature in Celsius
• C. IQ score
• D. Customer satisfaction on a 5-point scale

Answer: (A)

Ratio data have a true zero and equal intervals, which lets you meaningfully talk about ratios between values. Height in centimeters fits this because zero centimeters represents no height, and the distance between any two heights is consistent across the scale. This allows statements like 180 cm being twice 90 cm.

Temperature in Celsius isn’t ratio data because although its intervals are equal, zero does not mean the absence of temperature, so ratios aren’t meaningful. IQ scores are typically treated as interval data for the same reason: zero doesn’t indicate no intelligence, so ratios don’t have a true interpretation. A five-point satisfaction rating is ordinal—while higher numbers mean more satisfaction, the intervals between points aren’t guaranteed to be equal, and there’s no true zero for meaningful ratios.