Statistics for Business Management 2 (MGTC3111)
Higher Institute of Commerce and Management (HICM)
Semester: Resit
Level: 300
Year: 2014
UNIVERSITY OF BAMENDA
HIGHER INSTITUTE OF COMMERCE AND MANAGEMENT (HICM)
RESIT EXAMINATIONS
Academic year: 2013/2014, Date: September, 2014
Time allowed: THREE (3) HOURS. Time:
Examiners: Dr U.E Jumbo & Dr Dobdinga C.F
Course code: MGT 203 Credit value: 6
Course title: Statistics for Business Management II
INSTRUCTIONS: Students are expected to answer ALL the questions in the order in which they appear. SHOW ALL WORKING
Part I: (35 marks)
Lecturer; Dr. U.E Jumbo
Instructions Answer all the questions. Start each exercise on a new page
Exercise one: (10 marks)
1.
Give the difference between.
-
“a population” and “a sample”;
-
“a variable” and “an observation”;
-
“descriptive statistics"and “inferential statistics"
2.
Give the different types and sources of data.
3.
Write short notes on:
-
mutually exclusive events;
-
exhaustive events;
-
physical independence;
-
statistical independence.
-
Differentiate “the geometric distribution” from “the binomial
distribution”
Exercise two; (10 marks + 15 marks)
1. The discrete random variable X has probability distribution given by:
P(X=x)= P
x
=
,
= 1,2,3
0, ℎ
Determine, correct to 2 decimal places, the values of:
(i) the constant k,
(ii) the expectation of X,
(iii) the standard deviation
2. 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 ball 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 coloured white
Part II: (35 marks)
Answer all questions in this section
Q1) A simple random sample of size two is drawn from population with elements
{1,3,5,7,9), (i) Derive the sample means (ii) Determine the standard deviation of
(a) The population (b) the sample means (15 marks)
Q2) State and explain three desirable properties of an estimator
Q3) A standardized Business Statistics test was given to 50 girls and 75 boys.
The girls made an average grade of 76 with a variance of 36, while the boys made
an average grade of 82 with a variance of 64.
Find a 95% confidence interval for the difference in µ
1
and µ
2
, where µ
1
is the
mean score of all boys and µ
2
is the mean score of all girls who might take this test
(The 95% table value is 1.96)(6 marks)
Q4) The quantity sold by a company in a period of 9 days is, given as; 108, 105,
102, 104, 98, 100, 94, 102 and 96 tons. Find a 95% confidence interval for the
mean of the quantities sold, assuming an 4 approximate normal distribution (NB:
t
8,0.025
= 2.31) (8 marks)
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