An experiment investigated the effect of length and repetition of TV ads on students choosing to eat at Del Taco. All 60 students watched a 40-minute television program that included ads for Del Taco. Some students saw a 30-second commerical; others a 90-second commerical. The same commerical was shown either 1, 3, or 5 times during the program. After the viewing, each student was asked to rate their craving for Del Taco on a scale of 0 to 10. What are the levels of the length factor?
A.
30-second and 90-second commericals
B.
60 students
C.
1, 3, or 5 commercials during the 40-minute television program
D.
40-minute television program
E.
craving for Del Taco on a scale of 0 to 10