Interval data vs ratio data: which statement is true?

Interval data vs ratio data: which statement is true?

• A. Interval data has a true zero
• B. Interval data can have negative values
• C. Ratio data cannot be measured on a scale
• D. Ratio data has no meaningful zero

Answer: (B)

The key idea is how zero and negative values work on different measurement scales. Interval data have equal distances between values but no true zero point—the zero on an interval scale isn’t the absence of the quantity, so negative values can occur (think of temperature in Celsius or Fahrenheit). Ratio data, by contrast, have a true zero that means total absence of the quantity, so values are nonnegative and meaningful ratios can be formed (like height or Kelvin temperature). So the statement that interval data can have negative values is true. The other statements don’t fit because interval data do not have a true zero, ratio data can be measured on a scale, and ratio data do have a meaningful zero.

The key idea is how zero and negative values work on different measurement scales. Interval data have equal distances between values but no true zero point—the zero on an interval scale isn’t the absence of the quantity, so negative values can occur (think of temperature in Celsius or Fahrenheit). Ratio data, by contrast, have a true zero that means total absence of the quantity, so values are nonnegative and meaningful ratios can be formed (like height or Kelvin temperature). So the statement that interval data can have negative values is true. The other statements don’t fit because interval data do not have a true zero, ratio data can be measured on a scale, and ratio data do have a meaningful zero.