All of the following are examples of material culture except

You offer to trade your nickel for a dime held by a child. The child accepts the trade because the nickel is bigger. The child is

a. in the preoperational stage. b. in the neonatal stage of the growth sequence. c. obviously past the age of reason. d. displaying reversibility.

An appropriate correlation coefficient describing the relationship between two artificially dichotomous variables is

a. biserial correlation. b. phi coefficient. c. tetrachoric correlation. d. point biserial correlation.