My independent variable is assessment of whether respondents fear that crime is the worst problem in their city, and this assessment has 3 catagories (yes, uncertain, and no). I am looking at a data set in SPSS which lists all USA cities and many variables. My dependent variable are either number of single parent families in USA, number of black people in USA, number of people living below the poverty line. I can't say "the assessment affects number of people living below the poverty line". I thought about this for a long time, but can';t come up with a meaningful null hypothesis. Can you guys help? Thanks very much in advance.