Final answer:
Parametric tests are suitable for data measured on interval and ratio scales. These scales are preferred for parametric testing because they provide the necessary numerical properties for computations involving means, variances, and other statistical parameters.
Step-by-step explanation:
Parametric tests are statistical tests that assume data comes from a type of probability distribution and involve parameters such as mean and variance. These tests are suitable for data measured on interval and ratio scales. Interval scales have definite ordering and measurable differences between data points, though they lack a true zero point. In contrast, ratio scales have all the properties of interval scales with the addition of a meaningful zero point, allowing for the calculation of ratios.
Examples of data measured on an interval scale could include temperature scales like Celsius or Fahrenheit, where the difference between the degrees is meaningful, but 0 does not indicate the absence of temperature. Ratio scale examples include weights or lengths where 0 signifies no weight or length, and the differences and ratios have meaning.