1. Measures of Spread

2. How to find Quartiles

3. Interquartile Range (IQR) The difference between the third and first quartiles of a data set.

4. Outliers Value that is either much greater or much less than the median. Example: 15, 16, 18, 9, 18, 17, 19, 19, 4, 36 Median= 17.5 What are the outliers? 4 and 36

5. Find the first and third quartile of the set of data. 28, 25, 34, 44, 31, 2, 22, 23, 3, 24, 30 First find the median: 2, 3, 22, 23, 24, 25, 28, 30, 31, 34, 44 Find the first quartile: 2, 3, 22, 23, 24 22 Find the third quartile: 28, 30, 31, 34, 44 31 What’s the IQR? 9

6. What is the median? A.24 B.28 C.20 D.25 21, 25, 20, 28, 26

7. What is the first quartile? A.73 B.75 C.78 D.80 73, 75, 78, 82, 85, 93

8. Find all outliers for the data. 20, 16, 8, 12, 6, 31, 15, 14 A.none B.31 C.6 and 31 D.6

9. What is the Third quartile of the set of data? A.4.5 B.5 C.8.5 D.9 8, 3, 12, 5, 2, 9, 3

10. What is the IQR? A.6 B.12 C.15 D.16 16, 12, 20, 15, 12

11. Over 11 consecutive days, Mrs. S did the following number of pushups. 7, 8, 10, 10, 12, 14, 15, 17, 17, 19, 33. What is the upper quartile of the data? A.10 B.17 C.26 D.14

12. Find all outliers for the data. 28, 25, 34, 44, 31, 2, 22, 23, 3, 24, 30 A.2 B.2 and 44 C.44 D.2 and 3

13. Find the interquartile range of the data. 68, 15, 55, 5, 66, 42, 51, 12, 23 A.63 B.42 C.60.5 D.47

14. A.30.5 B.25 C.31 D.22.5 28, 25, 34, 44, 31, 2, 22, 23, 3, 24, 30

15. A.7 B.18 C.13.5 D.20.5 15, 12, 21, 18, 25, 11, 17, 19, 20

16. What is the lower quartile for the set of data? A.12 B.10.5 C.13.5 D.23.5 11, 21, 30, 29, 7, 26, 18, 12, 3, 10, 12, 15

17. Find all outliers for the data. 90, 95, 83, 101, 123, 57, 81, 88, 92 A.57 and 123 B.123 C.57 D.none

18. Find the interquartile range of the data. 189, 149, 155, 290, 141, 152 A.149 B.40 C.35 D.153.5