This exam tips covers Common Mistakes to Avoid 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 10 of 11 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
⚠️ Common Mistakes to Avoid
Table Construction:
- ❌ Using lower boundaries: Always use upper boundaries for grouped data
- ❌ Wrong running total: Each cumulative frequency must include all previous frequencies
- ❌ Final total doesn't match: Check your addition carefully
Graph Drawing:
- ❌ Straight lines: Should be smooth curves, not straight line segments
- ❌ Wrong starting point: Curve doesn't start at appropriate point
- ❌ Poor scale choice: Makes reading values difficult
Reading Values:
- ❌ Wrong direction: Going vertically first instead of horizontally
- ❌ Incorrect positions: Using wrong formula for quartile positions
- ❌ Inaccurate reading: Not following construction lines carefully
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.