ABSTRACT
To measure the amount of difference among participants, the researchers use the next two levels of measurement. They are referred to as continuous variables because they correspond to a continuous number line, so the intervals between measures can be quantified. Measurements at the interval and ratio levels have measurable distances among the scores they yield. The next level is ordinal. At this level, participants are placed in order from high to low, but the rank order does not correspond to a quantifiable amount, so researchers cannot be certain that the same distance exists between categories. The level at which researchers measure has important implications for data analysis, so there are references to scales of measurement throughout the discussion of statistics. In statistical tests, both variable type and variable scale of measurement largely determine the appropriate statistical test to carry out.
