finding interquartile range introduction
TRANSCRIPT
Finding: Interquartile Range (IQR) Introduction
- Mr Kim
Example 1Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Find the Median by crossing off the scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
**Make sure the scores are in Ascending Order
first!
Smallest to Biggest
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
So the Median (Q2) is in between 31 and 31which is 31
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Keep this line
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Now find the Median for both sides of the scores
by crossing off each side at a time
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
We will start with this side (it doesn’t matter
which side)
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
So the Lower Quartile (Q1) is in between 21 and
28 which is 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
So the Lower Quartile (Q1) is in between 21 and
28 which is 24.5
21+282
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Now do the same to the other side by crossing off
the scores
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
So the Upper Quartile (Q3) is in between 33 and 34 which is 33.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
So the Upper Quartile (Q3) is in between 33 and 34 which is 33.5
33+342
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Upper Quartile: 33.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Upper Quartile: 33.5
Interquartile Range: Upper Quartile – Lower Quartile
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Upper Quartile: 33.5
Interquartile Range: Upper Quartile – Lower Quartile
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Upper Quartile: 33.5
Interquartile Range: Upper Quartile – Lower Quartile 33.5 -
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Upper Quartile: 33.5
Interquartile Range: Upper Quartile – Lower Quartile 33.5 -
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Upper Quartile: 33.5
Interquartile Range: Upper Quartile – Lower Quartile 33.5 – 24.5
12 13 21 28 29 31 31 32 33 34 38 39
Finding IQR for even number of scores
Lower Quartile: 24.5
Upper Quartile: 33.5
Interquartile Range: Upper Quartile – Lower Quartile 33.5 – 24.5 = 9 Our Final Answer!
Example 2Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Same steps. Find the Median by crossing off
the scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
**Make sure the scores are in Ascending Order first!
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
So our Median (Q2) is 31
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Put 2 lines around it
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Now find the Median for both sides of the scores by crossing off each side
at a time
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
We will start with this side (it doesn’t matter
which side)
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
So the Lower Quartile (Q1) is in between 21 and 28
which is 24.5
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
So the Lower Quartile (Q1) is in between 21 and 28
which is 24.5
21+282
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Now do the same to the other side by crossing off
the scores
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
So the Upper Quartile (Q3) is in between 34 and
38 which is 36
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
So the Upper Quartile (Q3) is in between 34 and
38 which is 36
34+382
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Upper Quartile: 36
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Upper Quartile: 36
Interquartile Range: Upper Quartile – Lower Quartile
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Upper Quartile: 36
Interquartile Range: Upper Quartile – Lower Quartile
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Upper Quartile: 36
Interquartile Range: Upper Quartile – Lower Quartile 36 –
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Upper Quartile: 36
Interquartile Range: Upper Quartile – Lower Quartile 36 –
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Upper Quartile: 36
Interquartile Range: Upper Quartile – Lower Quartile 36 – 24.5
12 13 21 28 29 31 31 32 33 34 38 41 41
Finding IQR for odd number of scores
Lower Quartile: 24.5
Upper Quartile: 36
Interquartile Range: Upper Quartile – Lower Quartile 36 – 24.5 = 11.5 Our Final Answer!