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 into 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? Group of answer choices The sample size is too small to draw a valid conclusion. He has proven that heavy metal music causes rats to run slower and classical music causes rats to run faster. There is evidence that heavy metal music causes rats to run slower and classical music causes rats to run faster. We cannot draw any conclusion because of flaws in the experiment design.