7-7-3

Performing Statistical Calculations

 

Center Point

 

 

 

Center Point

 

1

2

3

4

5

6

7

8

9

Median

2 + 3

= Q1

7 + 8

= Q3

2

2

 

 

uChecked: Q1, Q3 on Data

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

Cumulative

Frequency

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)

 

0.1

0.2

 

0.4

 

 

0.7

0.8

0.9

1.0

1

2

3

3

4

4

4

5

6

7

Q1

Q3

 

20101001