Yoshi is testing how being exposed to pictures of different types of foods affects sleepiness. He shows each participant five pictures of dessert, five pictures of entrees, and five pictures of salads, and then he measures sleepiness after each group of five pictures. To eliminate order effects, Yoshi creates all possible sequences for presenting the three types of food and all five pictures in each type. He then randomly assigns each participant to a sequence. What technique is Yoshi using to prevent order effects

Apsychology student wishes to investigate differences in political opinions between business majors and political science majors at her college. she randomly selects 100 students from the 260 business majors and 100 students from the 180 political science majors. does this sampling plan result in a simple random sample? why or why not? no, because each group of 200 students in the sample does not have the same chance of being selected. yes, because each group of 200 students in the sample has the same chance of being selected. no, because each individual student does not have an equal chance of being selected. yes, because each individual student has the same chance of being selected.