An easy practice activity identifying threats to validity. A more difficult research example for your practice. There are four main number scales used in statistics. Each contains previous characteristics, as well as specific qualities. Type of Scale Characteristic Nominal Scale is build on specific categories.
All subjects can be in only one category.
Ordinal Scale is built on an order in which all subjects fit, showing relation to other subjects. Interval Scale is built with not only order, but with all intervals being equal. Ratio Scale has intervals, and a true zero point. Additional information on number scales , and a practice to see if you can classify examples. Describe examples of threats to internal validity and explain the limitations if these threats exist.