Which is the dependent and which is the independent variable in this example?

I was given a table of statistics entitled "Preterm Birth Rates for the 4 Regions in the US for all Ages" it then goes on to list the exact birth rate in each state in the given region and then the region as a whole.



So which is the dependent and which is the independent variable???Which is the dependent and which is the independent variable in this example?
Birth rate is dependent variable.
Age is independent variable.
State is independent variable.Which is the dependent and which is the independent variable in this example?
Not understanding exactly what the example is.

I think regions = independent because it is controlled for (I assume).

and preterm birth rates = dependent variable because it is what changes with respect to region.

But I don't have enough info to understand fully what your question is asking.Which is the dependent and which is the independent variable in this example?
does the birth rate depend on the state? or does the state depend on the birthrate?



state - independent

birth rate - dependent