Which of the following can be used to focus attention on the athlete's task and to mentally rehearse it beforehand?

Much of the existing research on media has focused on its

a. effects on the consumer. b. production and distribution. c. technological features. d. availability and cost.

Assume that of 55 persons who take a test, 10 of the 15 people falling in the upper group on total

test score and 5 of the 15 falling in the lower group on total test score pass a given item. What is the item discrimination index? A) 1.00 B) .33 C) .50 D) .17