Which level of measurement is considered interval-type with meaningful proportions and an absolute zero?

Which level of measurement is considered interval-type with meaningful proportions and an absolute zero?

• A. Interval
• B. Quasi-interval
• C. Ratio
• D. Nominal

Answer: (C)

The important idea here is having both equal intervals and a true zero. The ratio scale provides that: the steps between values are evenly spaced, and zero means the absence of the quantity, so you can meaningfully form ratios (for example, one length being twice another, or one weight being half of another). Interval scales have equal steps too, but their zero is arbitrary, so ratios aren’t meaningful—like temperature in Celsius, where 0 is just a point on the scale, and 20°C isn’t twice as hot as 10°C. Nominal scales are just categories without order, and ordinal scales have order but uneven gaps, so they don’t support meaningful ratios either. So the level that fits “interval-type with meaningful proportions and an absolute zero” is the ratio scale.

The important idea here is having both equal intervals and a true zero. The ratio scale provides that: the steps between values are evenly spaced, and zero means the absence of the quantity, so you can meaningfully form ratios (for example, one length being twice another, or one weight being half of another).

Interval scales have equal steps too, but their zero is arbitrary, so ratios aren’t meaningful—like temperature in Celsius, where 0 is just a point on the scale, and 20°C isn’t twice as hot as 10°C. Nominal scales are just categories without order, and ordinal scales have order but uneven gaps, so they don’t support meaningful ratios either.

So the level that fits “interval-type with meaningful proportions and an absolute zero” is the ratio scale.