Which measurement scale includes temperature in Celsius?

• A. Nominal
• B. Ordinal
• C. Ratio
• D. Interval

Answer: (D)

Temperature in Celsius uses an interval scale. The key idea is that the differences between temperatures are meaningful and equal across the scale—one degree represents the same amount of change anywhere. But the zero point at 0°C is arbitrary and does not mean “no temperature,” so you can’t meaningfully form ratios like twice as hot. That combination of equal intervals with an arbitrary zero is what makes Celsius an interval scale. Nominal and ordinal scales don’t capture these equal units between values, and a true zero that would allow ratios is not present in Celsius.