Interval/ratio data

If we are performing a test that has a continuous DV, then the variable must be measured at the interval or ratio level. It is important that the data has proportional intervals between levels of the variable, and ordinal variables often do not meet this assumption.

It is very important to avoid treating ordinal variables as continuous variables. We cannot calculate a mean or difference between ordinal values, but we can for continuous variables. What is often done–and is often inappropriate to do–is treat Likert-scale items as a continuous DV. What we can do is take a sum or average of multiple Likert-scale items and treat that sum or average as a continuous DV.

There is no “test” we can perform here. Rather, you will need to just recognize whether data is interval/ratio (continuous) or ordinal/nominal (categorical).