Inter quartile range

1. Interquartile Range
Conceptual Explanation
Interquartile Range

2. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
Interquartile Range

3. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
1 2 3 4 5 6 7 8 9
1
2
3
4
5
Interquartile Range

4. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
Interquartile Range

5. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
50th
percentile
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
Interquartile Range

6. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
50th
percentile
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
This is
called the
MEDIAN
Interquartile Range

7. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
50th
percentile
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
75th
percentile
Interquartile Range

8. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
50th
percentile
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
75th
percentile
This means that 25%
of the scores fall
below this point.
Interquartile Range

9. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
50th
percentile
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
75th
percentile
This means that 25%
of the scores fall
below this point.
This means that 75%
of the scores fall
below this point.
Interquartile Range

10. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
75th
percentile
Interquartile Range

11. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
75th
percentile
Interquartile Range

12. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
75th
percentile
50% of the scores fall
between these two
points
Interquartile Range

13. Interquartile Range
The interquartile range represents the distance
between the 25th percentile and 75th percentile.
1 2 3 4 5 6 7 8 9
1
2
3
4
5
25th
percentile
75th
percentile
50% of the scores fall
between these two
points
This is the Interquartile
Range!
Interquartile Range

14. Purposes of the Interquartile Range (IQR)
Interquartile Range

15. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
Interquartile Range

16. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
Interquartile Range

17. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
9t 8t 7t
7t
5t
6t
6t
5t 4t
6t
5t
5t
3d 2d 1st
1 2 3 4 5 6 7 8 9
1
2
3
4
5
3d4t
4t
Interquartile Range

18. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
9t 8t 7t
7t
5t
6t
6t
5t 4t
6t
5t
5t
3d 2d 1st
1 2 3 4 5 6 7 8 9
1
2
3
4
5
3d4t
4t First
Interquartile Range

19. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
9t 8t 7t
7t
5t
6t
6t
5t 4t
6t
5t
5t
3d 2d 1st
1 2 3 4 5 6 7 8 9
1
2
3
4
5
3d4t
4t FirstLast
Interquartile Range

20. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
2. Highly Skewed Data
Interquartile Range

21. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
2. Highly Skewed Data
1 2 3
3
5
4
4
5 6
4
5
5 7
7 22 23
1 2 3 4 5 6 7 23
1
2
3
4
5
6
6
22
Interquartile Range

22. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
2. Highly Skewed Data
1 2 3
3
5
4
4
5 6
4
5
5 7
7 22 23
1 2 3 4 5 6 7 23
1
2
3
4
5
6
6
22
Mean = 7
Median = 5
Interquartile Range

23. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
2. Highly Skewed Data
1 2 3
3
5
4
4
5 6
4
5
5 7
7 22 23
1 2 3 4 5 6 7 23
1
2
3
4
5
6
6
22
IQR
Interquartile Range

24. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
2. Highly Skewed Data
1 2 3
3
5
4
4
5 6
4
5
5 7
7 22 23
1 2 3 4 5 6 7 23
1
2
3
4
5
6
6
22
IQR Standard Deviation = 5.3
Interquartile Range

25. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
2. Highly Skewed Data
1 2 3
3
5
4
4
5 6
4
5
5 7
7 8 9
1 2 3 4 5 6 7
1
2
3
4
5
6
6
IQR
8 9
Standard Deviation = 2.3
Notice how the Standard
Deviation drops from
5.3 to 2.3.
Interquartile Range

26. Purposes of the Interquartile Range (IQR)
The Interquartile Range (IQR) is a helpful
measure of spread for two scenarios.
1. Rank ordered Data
2. Highly Skewed Data
1 2 3
3
5
4
4
5 6
4
5
5 7
7 8 9
1 2 3 4 5 6 7
1
2
3
4
5
6
6
IQR
8 9
Standard Deviation = 2.3
Notice how the Standard
Deviation drops from
5.3 to 2.3.
However the IQR stays
the same.
Interquartile Range

27. The End
Interquartile Range