Probability

Worked examples (9)

• 1Writing everyday statements in probability notation
• 2Deciding whether a value can be a probability
• 3Reading probabilities from a Venn diagram
• 4Applying the addition rule
• 5The addition rule checked against a region count
• 6Rearranging the addition rule to find an intersection
• 7Filling a Venn diagram from given probabilities
• 8Probabilities from a three-circle Venn diagram
• 9Showing that a set of probabilities cannot be consistent

Model answers (9)

• ✓Model answer — 0479 Paper 1 style — 7.1
• ✓Model answer — 0479 Paper 2 style — 7.1
• ✓Model answer — 0479 specimen Paper 1 Q2 style — 7.1
• ✓Model answer — 0479 Paper 1 style — 7.4
• ✓Model answer — 0479 Paper 2 style — 7.1, 7.4
• ✓Model answer — 0479 Paper 1 style — 7.4
• ✓Model answer — 0479 Paper 2 style — 7.1
• ✓Model answer — 0479 specimen Paper 1 Q2 style — 7.1, 7.4
• ✓Model answer — 0479 Paper 2 style — 7.4 (AO2)

Worked examples (9)

• 1Probability from a simple count
• 2Using a relative frequency as a probability
• 3The complement rule in three different forms
• 4Three chosen without replacement
• 5The same selection with replacement
• 6\
• 7One of each type, in any order
• 8Two teams formed one after the other
• 9Two independent trials — the denominator that does not fall

Model answers (9)

• ✓Model answer — 0479 Paper 1 style — 7.2, 7.3
• ✓Model answer — 0479 specimen Paper 2 Q6 context — 7.3
• ✓Model answer — 0479 specimen Paper 1 Q7(e) — 7.2, 7.3
• ✓Model answer — 0479 specimen Paper 1 Q6(a) — 7.2
• ✓Model answer — 0479 Paper 2 style — 7.2
• ✓Model answer — 0479 specimen Paper 1 Q6(b) — 7.2, 7.3
• ✓Model answer — 0479 specimen Paper 1 Q6(c) — 7.2
• ✓Model answer — 0479 specimen Paper 1 Q7(e) — 7.2
• ✓Model answer — 0479 specimen Paper 1 Q6(d) — 7.2

Worked examples (9)

• 1Restricting a two-way table to one row
• 2Restricting a Venn diagram to one circle
• 3Reading a conditional probability off a tree branch
• 4P(A given B) against P(B given A)
• 5The second pick of a selection is a conditional probability
• 6When the condition is itself a complement
• 7Running a tree backwards with expected frequencies
• 8Conditional probabilities on a three-circle Venn diagram
• 9Using conditional probabilities to compare two groups

Model answers (9)

• ✓Model answer — 0479 Paper 1 style — 7.6
• ✓Model answer — 0479 specimen Paper 1 Q2 style — 7.6
• ✓Model answer — 0479 specimen Paper 2 Q6 — 7.6
• ✓Model answer — 0479 Paper 2 style — 7.6
• ✓Model answer — 0479 specimen Paper 1 Q6 context — 7.6
• ✓Model answer — 0479 Paper 1 style — 7.6, 7.3
• ✓Model answer — 0479 specimen Paper 2 Q6 — 7.6
• ✓Model answer — 0479 specimen Paper 1 Q2 style — 7.6
• ✓Model answer — 0479 Paper 2 style — 7.6 (AO2)

Worked examples (9)

• 1Adding mutually exclusive outcomes
• 2Multiplying independent probabilities
• 3Completing a tree diagram
• 4Working out every path on a tree
• 5Testing whether two events are independent
• 6Classifying pairs of events
• 7A tree for selection without replacement
• 8Showing mutually exclusive events cannot be independent
• 9Three independent matches, and \

Model answers (9)

• ✓Model answer — 0479 specimen Paper 2 Q6 context — 7.5
• ✓Model answer — 0479 specimen Paper 1 Q7(e) context — 7.5
• ✓Model answer — 0479 specimen Paper 2 Q6(a) — 7.7
• ✓Model answer — 0479 specimen Paper 2 Q6 — 7.7
• ✓Model answer — 0479 specimen Paper 2 Q6 context — 7.5
• ✓Model answer — 0479 Paper 1 style — 7.5
• ✓Model answer — 0479 specimen Paper 1 Q6 context — 7.7
• ✓Model answer — 0479 Paper 2 style — 7.5
• ✓Model answer — 0479 Paper 2 style — 7.5, 7.3