Types of Data (Health Care)

Give an example of a research question that includes an independent and a dependent variable.  These are usually presented as, “How does A affect B?”, where A is your independent variable and B is your dependent variable.  Describe the independent and dependent variables in terms of whether they are nominal (also called categorical), ordinal, interval, or ratio variables (interval or ratio variables are also called continuous variables).  How would you study this research question?