A high school student named David Merrell did a study of how music affects the ability of rats to run a maze. He trained 71 rats to run a maze. Next he randomly divided the rats to three groups. Each group had 23 or 24 rats. For the next month, one group of rats listened all day to heavy metal music by the group Anthrax. One group listened all day to Mozart. One group never heard music. The rats ran the same maze three times a week for a month. The response variable is the time in seconds to complete the maze. By the end of the month he compared the average run time for each treatment group to the average run time for the control group. The Anthrax group was much slower at running the maze. The Mozart group was much faster. The differences are statistically significant at the 1% level. Run times are not heavily skewed in any group. What conclusion can we draw from these results?

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

Your food costs are $5,500. your total food sales are $11,000. what percent of your food sales do the food costs represent?

In a study of the relationship between socio-economic class and unethical behavior, 129 university of california undergraduates at berkeley were asked to identify themselves as having low or high social-class by comparing themselves to others with the most (least) money, most (least) education, and most (least) respected jobs. they were also presented with a jar of individually wrapped candies and informed that the candies were for children in a nearby laboratory, but that they could take some if they wanted. after completing some unrelated tasks, participants reported the number of candies they had taken. it was found that those who were identiď¬ed as upper-class took more candy than others. in this study, identify: (a) the cases, (b) the variables and their types, (c) the main research question, (d) identify the population of interest and the sample in this study, and (e) comment on whether or not the results of the study can be generalized to the population, and if the ď¬ndings of the study can be used to establish causal relationships.