are there variables in observational studies
Answer Wiki. There are no independent variables in observational studies. In an observational study, the researcher compares subjects against a control group and comes to a conclusion. Hypothetical example: if we have a research study comparing the risk of developing liver cancer between (1) people who drink some alcohol daily, and (2) teetotalers.
A correlation by definition, has no dependent and independent variable. It treats both variables equally. And each correlation is only about two variables. However, some people call observational studies correlational even if they use regressions. In a regression the independent variables are the ones you think predict or cause the dependent variable; or they are the ones under your control. Often the DV vs. IV distinction is one of substantive logic, not statistics.