Dependent and independent variables

Tell me which variables are dependent and independent? Why?

1. Teenage girls are better informed about the risks of venereal disease than teenage boys?

2. Infants born to heroin-addicted mothers have lower birthweights than infants of nonaddicted mothers.

3. Older nurses are less likely to express approval of the expanding role of nurses than younger nurses.

4. There is a relationship between tactile and auditory stimulation and heart rate response in premature infants.