Dr. smarty wanted to see if listening to his guided meditations on headphones would increase students' abilities to remember vocabulary words. to test his theory, he had students study vocabulary words. then, he had them listen to random music for five minutes before taking the vocabulary test. the next day, he had his students do it again, but this time had them listen to the guided meditation before taking the same vocabulary test again. dr. smarty was very excited to see that the students did much better the second day (after listening to his guided meditation) than they did the first day. what is the problem with dr. smarty's reasoning?