The superintendent wants to study the effects of phone distractions on math test scores In five math classes students were instructed to keep their phones face up on their desk while taking a math test In five other math classes student were instructed to keep their phones in their backpacks while taking the same math test After the tests the superintendent compared the scores Control Group Experimental Group Treatment Variable of Study QUESTION 33 A car insurance company divides their drivers by age The company then selects a few drivers from each age group to answer questions about speed limits What type of sampling method is this Cluster Sampling O Convenience Sampling O Stratified Random Sampling Systematic Sampling QUESTION 34 facturer is testing a new type of synthetic car oil with engine enhancers Their goal is to improve engine performance Two hundred cars that regularly use synthetic oil are placed into two different groups The first group will receive a cond group will receive the synthetic oil with the new engine enhancers Over the course of two years the manufacturer completes testing on the engine efficiency