Dr. ford wants to test the hypothesis that room color can affect memory. to that end, he randomly assigns 10 students to a condition where they study a written passage while seated in a room that is painted a lilac color. the other 10 students study the passage while seated in an identical room that is painted bright orange. after both groups studied the passage for one hour, they are given a multiple-choice test over the material. dr. ford then calculates how many questions the students in both groups answer correctly. dr. ford’s study is an example of a(n)