This key facts covers Key Facts About Cumulative Frequency within Cumulative Frequency for GCSE Mathematics. Revise Cumulative Frequency in Statistics for GCSE Mathematics with 14 exam-style questions and 20 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 11 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Key Facts About Cumulative Frequency
- Definition: The running total of frequencies up to each value
- Always increases: Each cumulative frequency is equal to or greater than the previous one
- Maximum value: The final cumulative frequency equals the total number of data items
- Grouped data: Uses the upper boundary of each group
- Median finding: The position n/2 locates the median class
- Quartiles: Q1 at n/4, Q3 at 3n/4 positions
- Graph shape: Always increases from bottom-left to top-right
Practice questions for Cumulative Frequency
Cumulative frequency is:
The graph shows the times for 60 students. The cumulative frequency at 40 seconds reads as 48. Estimate the number of students who took longer than 40 seconds to complete the puzzle.
Quick recall flashcards
How do you calculate cumulative frequency?
Start with the first frequency. For each subsequent class, add the current frequency to the previous cumulative frequency:
CF₂ = CF₁ + f₂
CF₃ = CF₂ + f₃, and so on.
What is cumulative frequency?
Cumulative frequency is the running total of frequencies up to and including each class. It shows how many data values fall below the upper boundary of each class.