How do outliers affect the mean, median, and mode?

Outliers can significantly affect the mean of a data set by pulling the average value towards them. If the outlier is significantly higher or lower than the other values in the set, it can increase or decrease the mean, respectively. This is because the mean is calculated by adding all the numbers in the data set and then dividing by the number of values.

The median, on the other hand, is less affected by outliers. The median is the middle value when the numbers are arranged in ascending or descending order. If there is an even number of values, the median is the average of the two middle numbers. Therefore, unless the outlier is one of the middle values, it will not affect the median.

The mode, which is the most frequently occurring number in a data set, is not affected by outliers unless the outlier occurs more frequently than the current mode.

In summary, outliers have a significant impact on the mean, less impact on the median, and usually no impact on the mode unless they are the most frequent values.