Skip to content

Course home

2.3 Probability

2.3 Probability

EasyMediumHard
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163
Question 83

The Human Resources director of a company is investigating the graduate status and salaries of its employees.

The event G G\,G is defined as the employee is a graduate.

The event H H\,H is defined as the employee earns at least £40 000 \pounds 40\,000\,£40000 a year.

For an employee chosen at random,

P(G∩H)=0.26P(G \cap H) = 0.26P(G∩H)=0.26, P(G∩H′)=0.19P(G \cap H') = 0.19P(G∩H′)=0.19, P(G′∩H)=0.11P(G' \cap H) = 0.11P(G′∩H)=0.11, P(G′∩H′)=0.44P(G' \cap H') = 0.44P(G′∩H′)=0.44

a(i).

Find P(G)P(G)P(G).

[1]
a(ii).

Find P[(G∩H)′]P\left[(G \cap H)'\right]P[(G∩H)′].

[2]
a(iii).

Find P(H∣G′)P(H \mid G')P(H∣G′).

[2]
b.

Determine whether the events G G\,G and H H\,H are independent. Fully justify your answer.

[2]
Markscheme

2.3 Probability Questions

  1. A Level
  2. /Maths
  3. /2.3 Probability

200 exam-style questions on OCR A Level Maths 2.3 Probability, covering 2.3.1 Mutually exclusive and independent events, 2.3.2 Diagrams to assist probability calculations, 2.3.3 Conditional probability (A-level only), 2.3.4 Conditional probability from first principles (A-level only), and 2.3.5 Modelling with probability. Each one has a worked solution and a mark scheme showing where the marks go.

Question bank