Two students in Ms. Romean's class are working on finding the mean for the following set of numbers: 2, 12, 16, 4, 18, 24, 32. Susan states that the answer is 15.4 when rounded to the nearest tenth. She added all of the numbers and divided by 7. Sam disagrees and thinks the answer is 54. She added all of the numbers and divided by 2. Which student is correct? How do you know? Explain your thinking!