Measurement Demo Summary
Prerequisites
Levels
of Measurement
When an interval scale such as sugar content is
mapped onto a rating scale such as judgment of sweetness, the
resulting rating scale is probably not an interval scale. For
most realworld situations, the means of ordinallevel rating
scales allow valid conclusions about the direction of the means
on the interval scale. However, it is theoretically possible for
means on the ordinal scale to be in the opposite direction from
means on the interval scale. Experts disagree on the importance
of this in realworld data analysis. We believe that the chances
of misinterpretation with real data are extremely low, and that
it is only with contrived artificial data and mappings of the
interval to the ordinal scale that these problems occur.
