An educational psychologist is testing the discriminant validity of a new measure of numerical learning difficulties. he gives his measure to a group of students along with another measure of verbal learning difficulties, which he predicts should not be strongly related to numerical learning difficulties. which of the following correlations would the psychologist hope to find in order to establish discriminant validity?

The school cafeteria can make pizza for approximately $0.30 a slice. the cost of kitchen use and cafeteria staff runs about $200 per day. the pizza den nearby will deliver whole pizzas for $9.00 each. the cafeteria staff cuts the pizza into eight slices and serves them in the usual cafeteria line. with no cooking duties, the staff can be reduced by half, for a fixed cost of $75 per day. should the school cafeteria make or buy its pizzas?