User interface language: English | Español

Date May 2017 Marks available 3 Reference code 17M.2.AHL.TZ1.H_5
Level Additional Higher Level Paper Paper 2 Time zone Time zone 1
Command term Find Question number H_5 Adapted from N/A

Question

When carpet is manufactured, small faults occur at random. The number of faults in Premium carpets can be modelled by a Poisson distribution with mean 0.5 faults per 20 m2. Mr Jones chooses Premium carpets to replace the carpets in his office building. The office building has 10 rooms, each with the area of 80 m2.

Find the probability that the carpet laid in the first room has fewer than three faults.

[3]
a.

Find the probability that exactly seven rooms will have fewer than three faults in the carpet.

[3]
b.

Markscheme

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

λ = 4 × 0.5      (M1)

λ = 2      (A1)

P ( X 2 ) = 0.677      A1

[3 marks]

a.

Y B ( 10 ,   0 , 677 )      (M1)(A1)

P ( Y = 7 ) = 0.263      A1

 

Note:     Award M1 for clear recognition of binomial distribution.

 

[3 marks]

b.

Examiners report

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

Syllabus sections

Topic 4—Statistics and probability » AHL 4.17—Poisson distribution
Show 71 related questions
Topic 4—Statistics and probability

View options