Mr. O'Lear is conducting an experiment that involves 10 plants. He initially determined that the plants had a mean height of 72 centimeters and a mean absolute deviation of 8.5 centimeters. He later discovered that he made two errors in the height measurements of two plants. The table shows the incorrect and the correct measurements of the two plants.
a) What is the correct mean height of the 10 plants?
b) What is the correct mean absolute deviation of the 10 plants?