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Maths Gcse Edexcel Higher

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  1. Scatter-Graphs-And-Correlation Edexcel Higher
    2 主题
  2. Cumulative-Frequency-And-Box-Plots Edexcel Higher
    4 主题
  3. Histograms Edexcel Higher
    3 主题
  4. Statistical-Diagrams Edexcel Higher
    7 主题
  5. Averages-Ranges-And-Data Edexcel Higher
    8 主题
  6. Combined-And-Conditional-Probability Edexcel Higher
    3 主题
  7. Tree-Diagrams Edexcel Higher
    1 主题
  8. Simple-Probability-Diagrams Edexcel Higher
    3 主题
  9. Transformations Edexcel Higher
    5 主题
  10. Vectors Edexcel Higher
    6 主题
  11. 3D-Pythagoras-And-Trigonometry Edexcel Higher
    1 主题
  12. Sine-Cosine-Rule-And-Area-Of-Triangles Edexcel Higher
    4 主题
  13. Pythagoras-And-Trigonometry Edexcel Higher
    4 主题
  14. Area-And-Volume-Of-Similar-Shapes Edexcel Higher
    1 主题
  15. Congruence-Similarity-And-Geometrical-Proof Edexcel Higher
    5 主题
  16. Volume-And-Surface-Area Edexcel Higher
    3 主题
  17. Circles-Arcs-And-Sectors Edexcel Higher
    2 主题
  18. Area-And-Perimeter Edexcel Higher
    4 主题
  19. Circle-Theorems Edexcel Higher
    7 主题
  20. Bearings-Scale-Drawing-Constructions-And-Loci Edexcel Higher
    5 主题
  21. Angles-In-Polygons-And-Parallel-Lines Edexcel Higher
    3 主题
  22. Symmetry-And-Shapes Edexcel Higher
    6 主题
  23. Exchange-Rates-And-Best-Buys Edexcel Higher
    2 主题
  24. Standard-And-Compound-Units Edexcel Higher
    5 主题
  25. Direct-And-Inverse-Proportion Edexcel Higher
    2 主题
  26. Problem-Solving-With-Ratios Edexcel Higher
    2 主题
  27. Ratios Edexcel Higher
    3 主题
  28. Sequences Edexcel Higher
    4 主题
  29. Transformations-Of-Graphs Edexcel Higher
    2 主题
  30. Graphing-Inequalities Edexcel Higher
    2 主题
  31. Solving-Inequalities Edexcel Higher
    2 主题
  32. Real-Life-Graphs Edexcel Higher
    4 主题
  33. Estimating-Gradients-And-Areas-Under-Graphs Edexcel Higher
    2 主题
  34. Equation-Of-A-Circle Edexcel Higher
    2 主题
  35. Graphs-Of-Functions Edexcel Higher
    6 主题
  36. Linear-Graphs Edexcel Higher
    4 主题
  37. Coordinate-Geometry Edexcel Higher
    4 主题
  38. Functions Edexcel Higher
    3 主题
  39. Forming-And-Solving-Equations Edexcel Higher
    3 主题
  40. Iteration Edexcel Higher
    1 主题
  41. Simultaneous-Equations Edexcel Higher
    2 主题
  42. Quadratic-Equations Edexcel Higher
    4 主题
  43. Linear-Equations Edexcel Higher
    1 主题
  44. Algebraic-Proof Edexcel Higher
    1 主题
  45. Rearranging-Formulas Edexcel Higher
    2 主题
  46. Algebraic-Fractions Edexcel Higher
    4 主题
  47. Completing-The-Square Edexcel Higher
    1 主题
  48. Factorising Edexcel Higher
    6 主题
  49. Expanding-Brackets Edexcel Higher
    3 主题
  50. Algebraic-Roots-And-Indices Edexcel Higher
    1 主题
  51. Introduction Edexcel Higher
    7 主题
  52. Using-A-Calculator Edexcel Higher
    1 主题
  53. Surds Edexcel Higher
    2 主题
  54. Rounding-Estimation-And-Bounds Edexcel Higher
    2 主题
  55. Fractions-Decimals-And-Percentages Edexcel Higher
    3 主题
  56. Simple-And-Compound-Interest-Growth-And-Decay Edexcel Higher
    4 主题
  57. Percentages Edexcel Higher
    3 主题
  58. Fractions Edexcel Higher
    4 主题
  59. Powers-Roots-And-Standard-Form Edexcel Higher
    4 主题
  60. Prime-Factors-Hcf-And-Lcm Edexcel Higher
    4 主题
  61. Number-Operations Edexcel Higher
    10 主题
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Exam code:1MA1

Conditional probability

What is a conditional probability?

  • A conditional probability is the probability of something happening (A) given that something else has already happened (B)

    • It is written straight P open parentheses A vertical line B close parentheses

      • Pronounced “the probability of A given B“

How do I calculate conditional probabilities?

  • Conditional probabilities must be out of a smaller restricted set of outcomes (not out of all possible events)

    • For example, if a computer randomly selects a digit from 1, 2, 3, 4, 5, 6, 7, 8, 9

      • P(it select a multiple of three) = 3 over 9

      • This is not a conditional probability

      • There are 3 possibilities (3, 6, 9) out of all 9 possibilities

    • However, if you program the computer to only select from even numbers, then

      • P(it selects a multiple of three given that it selects an even number) = 1 fourth

      • 1 possibility (6) out of only 4 possibilities (2, 4, 6, 8)

      • This is a conditional probability, written P(multiple of 3 | even) = 1 fourth

Examiner Tips and Tricks

  • Look out for conditional probability questions within larger questions on two-way tables, Venn diagrams or tree diagrams

    • They often use the phrase given that

Worked Example

A Venn diagram is shown below. The numbers represent numbers of people.

When 1 random person is selected, find straight P open parentheses A vertical line B close parentheses, simplifying your answer.

<img alt=”Venn diagram with two overlapping circles, A and B. A has 20, intersection 42, B has 63. Outside both is 14.” class=”ContentBlock_figure__vJw2q” data-nimg=”1″ decoding=”async” height=”1602″ loading=”lazy” sizes=”(max-width: 320px) 320w, (max-width: 640px) 640w, (max-width: 960px) 960w, (max-width: 1280px) 1280w, 1920w” src=”https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2025/05/62043_venndiagramwe.png” srcset=”https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=16/https://cdn.savemyexams.com/uploads/2025/05/62043_venndiagramwe.png 16w, https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=32/https://cdn.savemyexams.com/uploads/2025/05/62043_venndiagramwe.png 32w, https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=48/https://cdn.savemyexams.com/uploads/2025/05/62043_venndiagramwe.png 48w, https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=64/https://cdn.savemyexams.com/uploads/2025/05/62043_venndiagramwe

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