A researcher wants to test whether a certain sound will make rats do worse on learning tasks. It is known that ordinary rats can learn to run a particular maze correctly in 18 trials, with a standard deviation of 6 (The number of trials to learn this maze is normally distributed). The researcher is experimenting with 18 rats in the maze, but with the sound. These rats take an average of 38 trials to learn the maze.
Using the .05 level, what should the researcher conclude? Solve this problem explicitly using all five steps of hypothesis testing, and illustrate your answer with a sketch showing the comparison distribution, the cutoff (or cutoffs), and the score of the sample on this distribution.