Teach: Data Distribution ③ Relative Frequency

Data Distribution ③ Relative Frequency

The proportion of the total data represented by the frequency of each class is called relative frequency.

Relative frequency = frequency of the class ÷ total frequency

The sum of the relative frequencies is always 1 (or 100%).

📘 Example ①
If there are 20 data values and the frequency of a certain class is 5, find the relative frequency.
Answer:5 ÷ 20 = 0.25 (25%)
💡 Key Point
  • Relative frequency = frequency ÷ total
  • Sum of relative frequencies = 1
  • Use relative frequency when comparing data sets with different totals

Practice Problems

  1. There are 40 data values, and the frequency of the class 60-70 is 8. Find the relative frequency of this class.

Answer and Explanation

  1. Answer:0.2 (20%). 8÷40=0.2.

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