Deck 30: Introduction to Probability

Question 1

Which of the following statements about statistical experiments is NOT true?

A) Statistical experiments are always specially set up
B) Statistical experiments may be simple or complex
C) Statistical experiments may be repeated many times
D) Statistical experiments are designed to generate useful information

Answer 1

Statistical experiments are always specially set up

Question 2

A hotel stocks white, cream and blue pillowcases. Currently they have 400 white, 120 cream and 80 blue pillowcases. What is the probability of picking a blue pillowcase at random (3 decimal places)?

A) 0.133
B) 0.150
C) 0.185
D) 0.222

Answer 2

0.133

Question 3

A shipping company has 2 sizes of box each of which is available in 2 colours. If the probability of a box being 'large' is 0.62 and the probability of a box being 'grey' is 0.34 what is the probability of the next box being 'large' and 'grey' (2 decimal places)?

A) 0.15
B) 0.21
C) 0.34
D) 0.62

Answer 3

0.21

Question 4

A factory that fills bags of rice samples its production and found that out of 500 bags tested 350 were of the correct weight, 120 were too heavy and the remainder were too light. What is the empirical probability of a bag being too light (2 decimal places)?

A) 0.04
B) 0.06
C) 0.08
D) 0.10

Question 5

Which of the options below is the correct definition of an event set (E) that describes odd rolls of a 6-sided die?

A) E = {1,2,3,4,5,6}
B) E = {1,3,5}
C) E = {1}
D) E = {2,4,6}

Question 6

If p(E) = 0.35, which of the following options is the correct value of p()?

A) 0.35
B) 0.45
C) 0.55
D) 0.65

Question 7

A construction firm in Oman is running two projects (A and B). The probability that A will complete on time is 0.85 and the probability that B will complete on time is 0.65. What is the chance that only one of these projects will complete on time (2 decimal places)?

A) 0.35
B) 0.36
C) 0.37
D) 0.38

Question 8

Which of the following events are NOT independent?

A) 'the telephone will be answered by a woman' and ' the person answering the phone will have blue eyes'
B) 'it will rain today' and 'we will sell more raincoats'
C) 'the next car to arrive will be green' and 'the next car to arrive will have 2 occupants'
D) 'a particular supplier puts up their prices' and 'a particular customer will pay their bill on time'

Question 9

A company its IT equipment. It notes the computers over 3 years old and those that are laptops. Which of the following statements is NOT true?

A) Computers over 3 years old and laptops are not mutually exclusive
B) The intersection of computers over 3 years old and laptops may be empty (no laptops over 3 years old)
C) There are no items that could be in both sets
D) The intersection of computers over 3 years old and laptops may contain all elements (all computers are over 3 years old and laptops)