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6
2+3+1.
Class 7 · Bangla Version · Mathematics
Data, probability and written reasoning
Combine frequency data and independent probability.
About this lesson and its coverage
Original Kidemy Class 7 progression. This level has its own text, examples and questions. Curriculum versions share the progression; complete board-specific coverage still needs specification matching and additional material.
Learn the idea
A frequency counts occurrences. A weighted mean uses each value as many times as its frequency. Independence means one event does not change the model chance of another; it must be justified by the setup.
Worked example
Scores2,3,4 have frequencies1,2,1: mean=(2+6+4)/4=3. Two independent fair tosses give P(HH)=1/4.
- Identify the quantities and restrictions.
- Show a method with units or symbols.
- Check and explain the result.
Your written practice
Show your working on paper. Check your answer, then choose Next.
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11
1×2+2×3+3×1.
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1/36
1/6×1/6.
Write in your own words. A guardian or teacher should review this response.
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The bag’s composition and total both change.
Do not assume independence.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
The mean is 11/6, about 1.83 score units: the total score shared equally over 6 observations.
Give total, denominator and interpretation.
Progress and browser storage
Notebook challenge, sources and further study
Apply the idea
Prepare a frequency table and compare a with-replacement and without-replacement draw.
Review with a guardian or teacher
- Use the stated evidence or givens.
- Show reasoning rather than only a result.
- Review and explain one correction.
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