(Getting the answer without being sure you have asked the question) This is the randomized response technique due to Wamer (1965). You want to know the proportion of college students who have used drugs. A direct question will not give frank answers. Instead, you give the students a box containing four blue, three red, and four white balls. Each student is asked to draw a ball (you do not see the ball) and abide by the following instructions, based on the color of the ball drawn: Blue: Answer the question "Have you used drugs!" Red: Answer "yes." White: Answer "no." If 40% of the students answered "yes," what is the percentage of students who have used drugs?