Frequency Distributions — O/L Mathematics

What must I remember about Frequency Distributions?

• Grouped frequency distributions organize continuous numerical data into mutually exclusive class intervals with frequencies (f).
• Class boundaries and mid-values: Mid-value (class mark, x) = (Lower limit + Upper limit) / 2.
• Direct mean calculation formula: Mean (x̄) = (Σ fx) / (Σ f), where Σ fx is the sum of products of mid-values and frequencies, and Σ f is the total frequency.
• Assumed mean method formula: Mean (x̄) = A + (Σ fd) / (Σ f), where A is the chosen assumed mean and d = x - A is the deviation of each class mid-value.
• Modal class: The class interval containing the highest frequency in the distribution.

Test yourself (1 minute)

1. Assumed mean selection

   Always choose A from the mid-values (x) column, ideally near the center with a high frequency; NEVER choose A from the frequency column.

2. Deviation sign discipline

   d = x - A; deviations below A are negative, deviations above A are positive; sum Σ fd algebraically taking signs into account.

3. Stating the mean

   Ensure the final calculated mean carries the problem's physical units (e.g., kg, hours, Rs.) and is rounded to specified decimal places.

Practise Frequency Distributions questions today

Source: NIE G.C.E. (O/L) Mathematics Syllabus (Grade 10, Unit 25)

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Where does Frequency Distributions fit in the syllabus?

Grade 10 · Term 3