1. Lesson 2
Range and Quartiles

2. Measures of Spread: Range and IQR
Definitions
Range – the difference between the greatest and the least data values.
Quartiles – values that divide a data set into 4 equal parts.
The interquartile range (IQR) – difference between the 3rd and 1st quartile

4. Example 1
The April high temperatures for 5 years in Boston are 77o F, 86o F, 84o F, 93o F and 90o F.
Find the median, range, and the interquartile range (IQR).

5. Example 2
Find the mean, median, range and interquartile range for the given data sets.
21, 31, 26, 24, 28, 26

6. Example 3
Find the mean, median, range and interquartile range for the given data sets.
68, 71, 75, 74, 75, 71, 73, 71, 72, 74, and 79

7. A2
1. Find the range and interquartile range for 13, 14, 18, 13, 12, 17, 15, and 12.

8. 2. Find the range and interquartile range for 13, 12, 15, 17, and 9.