Question

The First quartile of a data set is 51, and the third quartile is 67. Which of these values in the data set is an outlier?

Answer 1

The outlier of a section is the number that is furthest away from the rest. Remember that a quartile is an area in a box plot — the first section is 51, meaning that only a small amount lower can be in the range. The third quartile is 67, meaning that only a small amount higher can be in the range.

Look at the highest and lowest numbers in your data set.

Highest point: 83
Lowest point: 29

In the first quartile, the data set is 51. You would then subtract the data set by the lowest point.

51 - 29 = 22

In the third quartile, the data set is 67. You would then subtract the highest point by the data set.

83 - 67 = 16

The one that is furthest away from the other areas of the data set would be the one with the highest number. 

The value 29 gave the highest number, meaning that is the outlier.