What is interval data?

Interval data is characterized by being ordered and having meaningful intervals between values, which allows for the measurement of the difference between them—not just in terms of ranking, but also quantifying the extent of those differences. For example, temperature in Celsius or Fahrenheit is interval data; the difference between 20 degrees and 30 degrees is the same interval as between 30 degrees and 40 degrees.

This type of data does not have a true zero point; for instance, zero degrees Celsius does not mean 'no temperature'—it is merely a point on the scale. This is a crucial aspect in defining interval data, as it allows for a wide range of mathematical operations including addition and subtraction, but not meaningful ratios or multiplications.

In contrast, the other categories provided do not accurately describe interval data. Absence of a variable pertains to a dichotomous or nominal description rather than an ordered scale. Data that cannot be compared would suggest a lack of any relational measurement, which does not align with the concept of interval data that is indeed comparable. Data represented as percentages typically falls into a different classification, often related to ratio or ordinal data, not fitting within the interval designation. Therefore, the characterization of interval data as ordered data with meaningful interval differences is the