Many children who live in the Slums of Tondo, Manila are developing asthma. In a descriptive study investigating this problem, parents whose children have asthma are asked about whether they smoke around their child, whether they live near a freeway, whether their child regularly seeks the services of a healthcare provider, their family income level, and also if there is a history in their family of asthma. Prior research has shown that these factors may have an influence on the development of asthma in children.

Questions: 

1. What are the variables that are under investigation in this Example C?

2. If you were the researcher in, what other variables would you study to see if it may contribute to asthma? Why? 

3. Given the variables presented in the Example C and the variables that you thought of, why would these variables be useful to the researcher?