7 Table 10.9 iclates occupational level (white collar, blue collar) and political party choice. controlling for income.

a) Construct the bivariate table between occupational level and political party, ignoring income is there an association? If so, describe it.

b) Do the partial tables display an association? Interpret them.

c) Using the nature of the association between income and each of the other variables. explain why the bivariate table has such different association than the partial tables

d) Do the partial tables exhibit statistical interaction? Explain.

e) Construct a chain diagram that might explain the relationships for these data. identify- ing the intervening variable.

f) Show that the data are also consistent with a spurious association, and draw the corre- sponding diagram. g) Refer to parts

(e) and

(f) Which diagrain seems more appropriate? Why?

TABLE 10.9 Medium Medium High Income High Income Low Income Low Income White Collar Collar Blue White Blue White Blue White Blue Collar Collar Collar Collar Collar Collar Democrat 45 5 100 25 75 300 45 405 Party Republican 405 45 300 75 25 100 5 45