# Statistics and Probability / Median and Interquartile Range

Activity 2 of 24
This lesson introduces students to the median, quartiles, and interquartile range for a distribution of data.

## Planning and Resources

Objectives
Students should understand  that summary measures of data identify certain key features of the distribution of the data, but do not necessarily give a complete picture of the distribution.  They can identify the median as a measure of center and interquartile range (IQR) as measure of spread related to the median.

Vocabulary
median
upper quartile
lower quartile
interquartile range (IQR)

Standard:

## Lesson Snapshot

#### Understanding

Dot plots display data in a way that makes it easier to identify the median of a set of data. This knowledge of median is the foundation for understanding interquartile ranges.

### What to look for

Students should note that there are the same number of points to the left and to the right of the median; regardless of the shape of the distribution.

### Sample Assessment

Identify the following as true or false.

a. The median is the midpoint between the smallest and largest values in the data set.

b. At most half of the values in a data set have values less than the median.

c. If you add 10 to every element of a data set, the median will not change.

d. If you add 10 to every element of a data set, the IQR will not change.