Show model answer and explanation
6
2+3+1.
Class 7 · English Medium · Cambridge · 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.
Show model answer and explanation
11
1×2+2×3+3×1.
Show model answer and explanation
1/36
1/6×1/6.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
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.
Keep your work on paper or in a local file. This page does not upload it or automatically grade the project.
Teacher-led lessons, schedules and prices for this outline are upcoming. You can use any starter practice above now without booking.
Your next step
Solo practice works without an account. Sign in to save a practice record to your learner profile.
Keep practising
Exact lesson links and related activities are labelled separately. Return-to-course links retain your selected learning path.