Which scale has equal intervals between values but no true zero, allowing addition and subtraction?

Which scale has equal intervals between values but no true zero, allowing addition and subtraction?

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

Answer: (B)

The scale in question is defined by having equal distances between values while lacking a true zero point. That combination means you can reliably measure how far apart two values are and perform addition and subtraction, but you can’t meaningfully multiply or form ratios because zero isn’t truly zero. A classic example is temperature on the Celsius scale: the difference between 20°C and 30°C is the same as between 80°C and 90°C, so intervals are equal, and you can add or subtract temperatures. But 0°C doesn’t mean “no temperature,” so you can’t say that 60°C is twice as hot as 30°C. Other scales don’t fit this description: nominal scales categorize without any order, and ordinal scales provide order but not equal intervals between steps. A ratio scale has a true zero, allowing meaningful ratios and all arithmetic, which is beyond what an interval scale allows.

The scale in question is defined by having equal distances between values while lacking a true zero point. That combination means you can reliably measure how far apart two values are and perform addition and subtraction, but you can’t meaningfully multiply or form ratios because zero isn’t truly zero. A classic example is temperature on the Celsius scale: the difference between 20°C and 30°C is the same as between 80°C and 90°C, so intervals are equal, and you can add or subtract temperatures. But 0°C doesn’t mean “no temperature,” so you can’t say that 60°C is twice as hot as 30°C.

Other scales don’t fit this description: nominal scales categorize without any order, and ordinal scales provide order but not equal intervals between steps. A ratio scale has a true zero, allowing meaningful ratios and all arithmetic, which is beyond what an interval scale allows.