Which example best illustrates interval data?

Interval data is characterized by a measurable scale where the differences between values can be quantified, and there is no true zero point that implies the absence of the quantity being measured. In this context, temperature is a perfect example, as zero degrees Fahrenheit and zero degrees Celsius represent specific points on the temperature scale but do not indicate a complete absence of temperature.

When temperatures are examined, the intervals between values are meaningful; for example, the difference in temperature between 10 degrees and 20 degrees is the same as between 20 degrees and 30 degrees. However, the zero points in these temperature scales do not signify "no temperature." This aspect distinguishes interval data from ratio data, which has a meaningful zero point indicating the absence of the measured attribute.

Other options do not fit this definition as neatly. For instance, distance in miles is a ratio data type because zero miles indicates the absence of distance. Similarly, tree species classification constitutes categorical data, and temperature in Kelvin, while also interval data, would combine aspects of a ratio characteristic due to its absolute zero point. Hence, zero degrees Fahrenheit and zero degrees Celsius succinctly exemplify the characteristics of interval data, providing clarity on how it differs from other data types.