All of the following variables, except for , would probably show a negative correlation.

A) average income and the incidence of dental disease
B) adult shoe size and IQ scores
C) the value of a car and the age of a car
D) hours spent watching TV and grade-point average

A negative correlation means that as one variable increases, the other decreases. Adult shoe size and IQ scores do not have this relationship; there's no reason to believe that changes in shoe size affect IQ or vice versa. The other options (A, C, D) suggest relationships where an increase in one variable could be associated with a decrease in the other (e.g., more income could mean less dental disease, a car's value generally decreases as it ages, and more hours watching TV could correlate with lower grades).