Answer:
Yes, the value that occurred most often would change. Before Martin's Tree Service bought two more saplings that were each 27 inches tall, the value that occurred most often was 26 inches. There were 6 saplings that were 26 inches tall, and no other height occurred more than 5 times. After Martin's Tree Service bought two more saplings that were each 27 inches tall, the value that occurs most often would be 27 inches. There would be 8 saplings that are 27 inches tall, and no other height would occur more than 7 times.
Here is a table of the heights of the saplings before and after Martin's Tree Service bought two more saplings that were each 27 inches tall:
Explanation: