Answer:
Option a) Mean
Mean is affected a lot by the change in the last observation as the median remains the same.
Step-by-step explanation:
we are given the following in the question:
Data set A: 64, 65, 66, 68, 70, 71, 72
Data set B: 64, 65, 66, 68, 70, 71, 720
For data set A, the mean and median are 68.
For data set B:
Formula:

Sorted data:
64, 65, 66, 68, 70, 71, 720

Clearly, 720 is the is a outlier.
As seen mean is affected a lot by the change in the last observation as the median remains the same.