Statistics for Business Management 1 (MGTC2206)
Higher Institute of Commerce and Management (HICM)
Semester: Second Semester
Level: 200
Year: 2015
HIGHER INSTITUTE OF COMMERCE AND MANAGEMENT(HICM)
Statistics for Business Management II. Course code
MGC20
Date 2
nd
march 2015 Time 8:00am-10:30am
Lecturer: Dr. U.E. Jumbo
Instructions: Answer all questions and start each exist on a new page
Exercise 1 (15marks)
1. Write short notes on:
Mutually exclusive events;
Exhaustive events;
2. Give the characteristics of “ the binomial distribution”
3. Tabulate the probability distribution of a number of heads obtained when a fair coin is tossed
twice
4. Tabulate the probability distribution of a number of heads obtained when a fair coin is tossed
three times.
Exercise 2: (10marks+ 10marks)
The discrete random variable X has probability distribution given
(X=x)=Px =
( = 1,2,3)
0 ℎ
Determine correct to two decimal places the value of
a) the constant k;
b) The expectation of X.
c) The standard deviation of X.
A bag contains 7 white balls and 3 black balls. A white box contains 5 green balls and 2 red balls. A
block contains 3 green balls and 1 red ball. A ball is taken at random from the bag and if this white ball
is taken at random from the white box. If it is a black a ball is taken at random from the white box.
Given that the ball taken from the box is red, determine the probability that the box is source white.
PART II- Lecturer Dr. Dobdinga C.F.
ANSWER ALL QUESTIONS
Question one (12+8)MARKS
a) A population is made up of {3,7,8,12}. Assuming ample size of the two drawn without
replacement from the population. Find i) µ and ó ii) µ
3
and ó
3
NB show the simple sizes
obtained on statistical table. iii) If sampling done with replacement find µ
3
and ó
3
without
presenting the statistical table.
b) Consider the following estimation 1=
and x2=
verify for Biasedness
and efficiency
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Question Two
a) The kidding properties of a snow have been tested and mean skid distance of 154m has been
established for standardized conditions. A new and more expensive tire as developed, but
rests on a sample of 20 tires yield mean skid, distance of 141m. Because of the cost involved,
the new tires will variance of 144m. Because of the cost involved the new tires will be
purchased only if they skid less at the 5 percent level of significance. Based on the sample,
will the new tires be purchased?
b) A sample of 75 randomly selected newborn produce the following results
Boys
Girls
n=40
n=35
Mean=3.9kg
Mean=3.18kg
Standard deviation=0.44kg
Variance=0.28kg
i) Construct a 95 percent confidence interval for the difference in the mean weight
between boys and girl (Boys minus girls)
At the 5 percent level of significance, test the claim that there is no difference between the weights of
newborn boys and girls.
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