Introduction
Arithmetic mean
Median
8. Median – properties
Mode
Summary

Instruction

The median is resistant to extreme observations. Consider the table below:

Set Sorted Median
1, 1, 1, 1 1, 1, 1, 1 1
1, 1, 1, 9 1, 1, 1, 9 1
1, 1, 1, 97 1, 1, 1, 97 1
1, 1, 1, 997 1, 1, 1, 997 1
1, 1, 1, -1003 1, 1, 1, -1003 1

Changing one element in the set in the given example doesn't change the median. This is completely different from the behavior of the arithmetic mean.