6-8
Center Point Center Point
S OnData
The Q1 and Q3 values for this calculation method are described below.
Q1 = {value of element whose cumulative frequency ratio is greater than 1/4 and nearest to
1/4}
Q3 = {value of element whose cumulative frequency ratio is greater than 3/4 and nearest to
3/4}
The following shows an actual example of the above.
(Number of Elements: 10)
Data Value Frequency
Cumulative
Frequency
Cumulative
Frequency Ratio
1 1 1 1/10 = 0.1
2 1 2 2/10 = 0.2
3 2 4 4/10 = 0.4
4 3 7 7/10 = 0.7
5 1 8 8/10 = 0.8
6 1 9 9/10 = 0.9
7 1 10 10/10 = 1.0
• 3 is the value of whose cumulative frequency ratio is greater than 1/4 and nearest to 1/4, so
Q1 = 3.
• 5 is the value of whose cumulative frequency ratio is greater than 3/4 and nearest to 3/4, so
Q3 = 5.
Reference Point (0.25) Reference Point (0.75)
Median
1 234567 98
= Q1
2
2
+
3
= Q3
2
7
+
8
Median
1 234567 98
= Q1
2
2
+
3
= Q3
2
7
+
8
Q1
0.1 0.2 0.4 0.7 0.8 0.9 1.0
Q3
1
2633444 75
Q1
0.1 0.2 0.4 0.7 0.8 0.9 1.0
Q3
1
2633444 75