Relative Frequency
POINT
Relative frequency = frequency of the class ÷ total frequency. The relative frequencies add up to 1.
EXAMPLE
Find A, B and C in the frequency table.
| Class interval | Frequency | Relative frequency |
|---|---|---|
| 0–10 | 6 | 0.15 |
| 10–20 | 8 | B |
| 20–30 | A | C |
| 30–40 | 12 | 0.30 |
| 40–50 | 4 | 0.10 |
| Total | 40 | 1.00 |
A = 40 − (6 + 8 + 12 + 4) = 10
B = 8 ÷ 40 = 0.20
C = 10 ÷ 40 = 0.25
Practice
Complete the frequency and relative frequency table.
01
| Class interval | Frequency | Relative frequency |
|---|---|---|
| 0–10 | 5 | 0.17 |
| 10–20 | 7 | ? |
| 20–30 | ? | ? |
| 30–40 | 6 | 0.20 |
| 40–50 | 3 | 0.10 |
| Total | 30 | 1.00 |
Frequency (20–30) = 9
Relative frequency (10–20) = 7 ÷ 30 = 0.23
Relative frequency (20–30) = 9 ÷ 30 = 0.30
02
| Class interval | Frequency | Relative frequency |
|---|---|---|
| 0–10 | 4 | ? |
| 10–20 | 10 | 0.25 |
| 20–30 | 8 | 0.20 |
| 30–40 | ? | ? |
| 40–50 | 6 | 0.15 |
| Total | 40 | 1.00 |
Frequency (30–40) = 12
Relative frequency (0–10) = 4 ÷ 40 = 0.10
Relative frequency (30–40) = 12 ÷ 40 = 0.30
03
| Class interval | Frequency | Relative frequency |
|---|---|---|
| 0–10 | 8 | 0.27 |
| 10–20 | ? | ? |
| 20–30 | 7 | 0.23 |
| 30–40 | 4 | 0.13 |
| 40–50 | 6 | ? |
| Total | 30 | 1.00 |
Frequency (10–20) = 5
Relative frequency (10–20) = 5 ÷ 30 = 0.17
Relative frequency (40–50) = 6 ÷ 30 = 0.20
04
| Class interval | Frequency | Relative frequency |
|---|---|---|
| 0–10 | 6 | 0.15 |
| 10–20 | 9 | 0.23 |
| 20–30 | 5 | ? |
| 30–40 | 8 | 0.20 |
| 40–50 | ? | ? |
| Total | 40 | 1.00 |
Frequency (40–50) = 12
Relative frequency (20–30) = 5 ÷ 40 = 0.125
Relative frequency (40–50) = 12 ÷ 40 = 0.30
05
| Class interval | Frequency | Relative frequency |
|---|---|---|
| 0–10 | ? | ? |
| 10–20 | 6 | 0.15 |
| 20–30 | 11 | 0.28 |
| 30–40 | 7 | ? |
| 40–50 | 13 | 0.33 |
| Total | 40 | 1.00 |
Frequency (0–10) = 3
Relative frequency (0–10) = 3 ÷ 40 = 0.075
Relative frequency (30–40) = 7 ÷ 40 = 0.175