# Measures of Variability : Interquartile Range

Let's look at a couple of examples.

Find the interquartile range of the following data.

Example 1:

1, 7, 0, 7, 2, 6, 3, 6, 0, 7, 8

First make sure that it is in order from

**to**

*least***.**

*greatest*0, 0, 1, 2, 3, 6, 6, 7, 7, 7, 8

Find the median:

_{2})

Find the middle of the

_{1}= 1

Find the middle of the

_{3}= 7

Example 2:

Put in order from

**to**

*least*

*greatest*find the average

Find the median 1, 1, 4, 5, 5, 5, 6, 7, 8, 9, 10, 12

Find Q

_{1}the median of the lower half

1, 1, 4, 5, 5, 5, 6, 7, 8, 9, 10, 12

Find Q

_{3}the median of the upper half

1, 1, 4, 5, 5, 5, 6, 7, 8, 9, 10, 12

Let's look at an example when given a box and whisker plot.

Min Q

_{1}Med Q

_{3}Max

**: to find the**

*A quick review***you will put the data in order from least to greatest then find the median. Once you have found the median Q**

__interquartile range___{1}is the median of the first half of the data and Q

_{3}is the median of the second half of the data.

Related Links:Math algebra Measures of Variability : Range Parts of An Expression |

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