Statistics for Economics and Business 2 Questions

Faculty of Economics and Management Science (FEMS)

Semester: Second Semester

Level: 200

Year: 2016

Duration:3 hours

Instruction: answer all.

EXERCISE 1: (20 marks)

A bag contains 7 white balls and 3 black balls. A white box contains 5 green balls and 2 red

balls. A black box contains 3 green balls and 1 red ball. A ball is taken at random from the bag,

and if this is white, a ball is taken at random from the white box. If it is black a ball is taken at

random from the black box. Given that the ball taken from the box is red, determine the

probability that the box is colored white.

EXERCISE 2: (20 marks)

1. The random variable X has a poisson distribution with mean 1.7. determine the

probability P(X>3).

2. The random variable Y has a poisson distribution with mean 1.4. determine the

probability that Y takes a value greater than 4, but less than 7.

3. The discrete random variable X has a binomial distribution with n=60 and p=0.02

determine P(X=1)

EXERCISE 3: (15 marks)

Five chairs are arranged in a line. Five boys are to be seated on the chairs. If Alfred and Brice sit

next to each other then, a fight is sure to start.

1. How many possible arrangements are there id there are no restrictions on the seating

arrangements?

2. If the boys are assigned seats at random, what is the probability that Alfred and Brice are

not sitting next to one another?

EXERCISE 4: (15 marks)

A car is made in three versions: 2-door, 4-door and hatchback. The proportions of the three types

made are 25%, 40% and 35% respectively. Each version of the car has either a 1400cc engine or

a 1600cc engine. Of the 2-door version, 70% have 1400cc engines. The proportions for the 4-

door and hatchback versions are 40% and 35% respectively.

In a publicity stunt the car makers choose an owner at random to receive a prize of free servicing

for the lifetime of the car. Determine the probability that the owner’s car has a 1600cc engine.

THE UNIVERSITY OF BAMENDA

FACULTY OF ECONOMICS AND MANAGEMENT SCIENCES

2nd Semester Exam

Course e: Statistics for Econs and Business 2

Course Code: ECON206

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