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Date November 2015 Marks available 2 Reference code 15N.2.hl.TZ0.1
Level HL only Paper 2 Time zone TZ0
Command term Find Question number 1 Adapted from N/A

Question

The events A and B are such that P(A)=0.65, P(B)=0.48 and P(AB)=0.818.

Find P(AB).

[2]
a.

Hence show that the events A and B are independent.

[2]
b.

Markscheme

Note:     In Section A, where appropriate, accept answers that correctly round to 2 sf except in Q2, Q5(a) (ii), Q5(b) and Q8(a).

 

0.818=0.65+0.48P(AB)     (M1)

P(AB)=0.312     A1

[2 marks]

a.

P(A)P(B)=0.312(=0.48×0.65)     A1

since P(A)P(B)=P(AB) then A and B are independent     R1

 

Note:     Only award the R1 if numerical values are seen. Award A1R1 for a correct conditional probability approach.

[2 marks]

Total [4 marks]

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Topic 5 - Core: Statistics and probability » 5.3 » Combined events; the formula for P(AB) .

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