Mõõteskaalad

Mõõteskaalad are fundamental concepts in statistics and research, representing different levels of measurement for variables. Understanding these scales is crucial for choosing appropriate statistical analyses and interpreting data correctly. There are four primary types of measurement scales: nominal, ordinal, interval, and ratio.

The nominal scale is the simplest, categorizing data into distinct groups without any inherent order or ranking. Examples include gender (male, female), blood type (A, B, AB, O), or color (red, blue, green). Arithmetic operations are not meaningful for nominal data.

The ordinal scale also categorizes data but introduces a meaningful order or rank. However, the difference between the ranks is not necessarily equal or quantifiable. Examples include survey responses like "disagree," "neutral," "agree," or educational levels such as "high school," "bachelor's," "master's." While we know one category is "higher" than another, we cannot quantify the difference.

The interval scale measures data with equal intervals between values, but it lacks a true zero point. This means that zero does not represent the absence of the measured quantity. Temperature in Celsius or Fahrenheit is a common example. While the difference between 10°C and 20°C is the same as between 30°C and 40°C, 0°C does not mean there is no temperature.

The ratio scale is the most informative, possessing equal intervals and a true zero point, indicating the complete absence of the quantity being measured. Examples include height, weight, age, or income. With ratio scales, we can perform all arithmetic operations, and statements like "twice as tall" or "half the price" are meaningful.