1.6 An automobile manufacturer observes the demand for its brand
increasing as per capita income increases. Sales increases also
follow low interest rates, which ease credit conditions. Buyer
purchase behavior is seen to be dependent on age and gender. Other
factors influencing sales appear to fluctuate almost randomly
(competitor advertising, competitor dealer discounts, introductions
of new competitive models). a If sales and per capita income are
positively related, classify all variables as dependent,
independent, moderating, extraneous, or intervening. b Comment...