Probability and Statistics (GSDR2109)

Higher Institute of Transport and Logistics (HITL)

Semester: First Semester

Level: 200

Year: 2017

Answers (200 )
School/Faculty: HITL
DEPARTMENT: LECTURER(S): Dr. Nukenine S. L. Konje
Academic Year: 2016/2017 CA
COURSE TITLE: Probability and Statistics
DATE: 12/04/2017 TIME: 2 hours
Instructions: Answer all questions
THE UNIVERSITY OF BAMENDA
P.O BOX 39 Bambili
REPUBLIC OF CAMEROON
Peace-Work-Fatherland
0 .
. 17 0
Problem 1 (6 points)
Define the following with respect to Statistics and Probability: (i) A population, (ii) A sample
Random Sample (iii) An Experiment, (iv) A sample space, (v) A Random Variable
Problem 2 (9 points)
A sample random sample of containers is chosen from a large population of containers in a
certain railway terminal. The heights (in inches) of containers are given as;
30, 223, 232, 223, 75, 80, 80, 126, 105, 149, 179
179, 79, 191, 236, 240, 242, 245, 247, 254, 274, 384, 470
Using the given data, calculate the following:
(i) The sample mean (ii) The sample media (iii) The 65
th
percentile of the sample
Problem 3 (5 points)
Customers who purchase a certain type of vehicle can order vehicles in any of the three types. Off all
vehicles sold, 45% are passenger cars, 35% are Sport Utility Vehicles and 20% are Pick-up trucks. Of
the passenger cars, 10% fail a quality control test within two years of purchase, while 12% of sport
utility vehicles and 15% of pick-up trucks fail the test; what is the probability that a randomly selected
vehicle will fail a quality control test within two years.
Problem 4 (5 points)
1 cm length copper wire is manufactured by a certain process. The number of flaws in each copper
wire manufactured varies from wire to wire; overall, 48% of the wires produced have no flaws, 39%
have one flaw, 12% have two flaws and 1% has no flaws. Let X be the number of flaws in a randomly
selected piece of copper wire. (a) What is the probability Mass function X? (b) and F(2) and F(1.5),
given that F(x) denotes the cumulative function of X (c) Calculate the Mean, variance and standard
deviation for X.
SUCCESS WISHES!!!
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