Some questions are more readily answered using quantitative techniques, and others are best addressed through qualitative techniques or a combination of both approaches.
Suppose you are interested in how a parent's alcoholism affects the life of an adolescent.
Develop a research question best answered using quantitative techniques and another research question better suited to qualitative techniques.
A quantitative question is, "Are adolescents with alcoholic parents more likely to have criminal records?" and a qualitative question is, "What issues do alcoholic parents introduce in their adolescent's peer relationships?"