The control group's score of 47.26 on the pretest put it at the 26th percentile. Does this percentile score represent nominal, ordinal, or interval scale data?
To determine the scale of data represented by the percentile score, we need to understand the characteristics of the specific scales.
Nominal scale: This scale categorizes data into distinct categories or labels where no ordering or ranking is possible. Examples include gender, eye color, or blood type.
Ordinal scale: This scale not only categorizes data into distinct categories, but also assigns an order or ranking to them. However, the intervals between the categories are not uniform or comparable. Examples include educational levels (e.g., elementary, middle, high school), letter grades (A, B, C, etc.), or sports rankings (1st place, 2nd place, 3rd place).
Interval scale: This scale categorizes data into distinct categories, assigns an order or ranking to them, and also has uniform and comparable intervals between the categories. Examples include temperature (in Celsius or Fahrenheit), time (on a 24-hour clock), or IQ scores.
Based on the information provided, we know that the control group's score of 47.26 represents its placement at the 26th percentile. Percentiles are relative measures that help compare an individual's score to a larger group. Since the percentile score represents where the control group's score falls within a distribution (from lowest to highest), it implies an ordinal scale.
Therefore, the percentile score represents an example of ordinal scale data.