3.17. In 2003 in the United States, the median family income was $55,800 for white families, $34,400 for black families, and $34,300 for Hispanic families (Statistical Abstract of the United States, 2006).

(a) Identify the response variable and the explanatory variable for this analysis.

(b) Is enough information given to find the median when all the data are combined from the three groups? Why or why not?

(c) If the reported values were means, what else would you need to know to find the overall mean?