Statistics & Probability Revision Notes for IGCSE Maths
These comprehensive revision notes cover everything you need to know about statistics & probability for the Cambridge IGCSE Mathematics 0580 examination. Written by Teacher Rig, each section includes key concepts, essential formulas, and practical exam tips to help you achieve your best grade.
Averages and Spread
Mean = sum of all values / number of values. Median = middle value when arranged in order. Mode = most frequent value. Range = highest - lowest. For grouped data, use midpoints to estimate the mean. The median class is found using the cumulative frequency.
Key Formulas
- Mean = sum of values / n
- Estimated mean = sum of (midpoint x frequency) / total frequency
- Range = maximum - minimum
Exam Tips
- For grouped data, the mean is an ESTIMATE because we use midpoints
- The median of n values is the ((n+1)/2)th value for listed data
- Mode is the only average you can use for non-numerical data
Probability Basics
Probability ranges from 0 (impossible) to 1 (certain). P(event) = number of favourable outcomes / total number of outcomes. P(not A) = 1 - P(A). For mutually exclusive events: P(A or B) = P(A) + P(B). For independent events: P(A and B) = P(A) x P(B).
Key Formulas
- P(A) = favourable outcomes / total outcomes
- P(not A) = 1 - P(A)
- P(A or B) = P(A) + P(B) for mutually exclusive events
- P(A and B) = P(A) x P(B) for independent events
Exam Tips
- Probabilities must be between 0 and 1
- All probabilities for a complete set of outcomes must sum to 1
- OR means add, AND means multiply (for independent events)
Tree Diagrams and Conditional Probability
Tree diagrams show all possible outcomes of two or more events. Multiply along branches (AND), add between branches (OR). For 'without replacement' problems, the probabilities change on the second draw because the total number of items has decreased.
Key Formulas
- Along branches: multiply
- Between branches: add
- Without replacement: reduce totals
Exam Tips
- Each set of branches must sum to 1
- For without replacement, both the numerator and denominator change
- Draw the full tree diagram before calculating - it helps you see all possibilities
Histograms
In a histogram, the area of each bar represents the frequency, not the height. The y-axis shows frequency density = frequency / class width. This is important when class widths are unequal.
Key Formulas
- Frequency density = frequency / class width
- Frequency = frequency density x class width
Exam Tips
- The y-axis is frequency DENSITY, not frequency
- The area of each bar gives the frequency for that class
- To find frequency from a histogram, calculate area = width x height
Revision Checklist
- I understand all key concepts in statistics & probability
- I have memorised the essential statistics & probability formulas
- I can apply these concepts to exam-style questions
- I have practised past paper questions on statistics & probability
- I know the common mistakes to avoid in statistics & probability questions
Frequently Asked Questions
What statistics & probability topics are covered in IGCSE Maths?
The IGCSE 0580 syllabus covers statistics & probability across both Core and Extended tiers. Key areas include averages and spread. Key areas include cumulative frequency and cumulative frequency diagrams. Key areas include probability basics.
How important is statistics & probability in the IGCSE exam?
Statistics & Probability is a significant part of the IGCSE Mathematics exam, typically appearing in Paper 2 (non-calculator) and Paper 4 (calculator). Questions range from straightforward calculations to multi-step problems that combine statistics & probability with other topics.
What are the most common mistakes in statistics & probability?
Common mistakes include not showing full working, forgetting to state units, misreading the question, and rushing through calculations. For statistics & probability specifically, make sure you understand the underlying concepts rather than just memorising procedures.
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