Question

How does an outlier affect the mean of a data set?

Answer 1

Outliers are numbers in a data set that are vastly larger or smaller than the other values in the set:

The mean is non-resistant, which implies it is affected by outliers. More specifically, the mean will want to move towards the outlier.

For example: For a data set, $1,2,3.$

The mean is $\frac{1+2+3}{3}=2$

But if we add an outlier of $50$ to the data set,

Then the mean is $\frac{1+2+3+50}{4}=14$

Hence, the mean moved towards the outlier.