THE OPEN UNIVERSITY OF SRI LANKA
BACHELOR OF MANAGEMENT STUDIES (HONORS) DEGREE PROGRAMME
LEVEL 5
ACADEMIC YEAR: 2019/2020
MCU3209/ MSU5509 – QUANTITATIVE TECHNIQUES FOR MANAGEMENT II
Deadline for Submission: - 08/03/2020 (On or Before)
Instructions:
Late Assignments will not be accepted.
Answers should be clearly handwritten or typed on the A4 size paper.
Write your student registration number in every answer script
Plagiarism is considered an offense.
ASSIGNMENT NO: 509
Guidelines:
This assignment is based on the concepts of probability distributions, confidence intervals and hypothesis testing.
Refer the day school presentations that are uploaded to MyOUSL as supplementary material. You may search
online for further knowledge. Answer the following questions.
(1) Sociologists say that 90% of married women claim that their husbands mother is the biggest bone ofcontention in their marriages. Suppose that 10 married women are having coffee together one
morning. Find the probability that at least 5 of them dislike their mother in law. Use the Binomial
distribution probability formula to find the answer.
(2) A bank is interested in studying the number of people who use the ATM located outside its office
late at night. On average, 1.6 customers walk up to the ATM during any 10 minute interval between
9pm and midnight. What is the probability of more than 3 customers using the ATM during any 10
minute interval?
(3) A coffee shop serves an average of 70 customers per hour during the morning rush. Find the
probability that less than 55 customers arrive in an hour during tomorrow's morning rush.
(4) The repair time for air conditioning units is believed to have a normal distribution with a mean of
40 minutes and a standard deviation of 14 minutes. Find the probability that the repair time for an
air conditioning unit will be between 32 and 42 minutes.
(5) Overbooking of passengers on intercontinental flights is a common practice among airlines.
Aircraft which are capable of carrying 200 passengers are booked to carry 210 passengers. If on
average 8% of passengers who have a booking fail to turn up for their flights, what is the
probability that at least two passengers who has a booking will end up without seats on a particular
flight?
(6) A company manufactures batteries that the CEO claims will last an average of 350 hours under
normal use. A researcher randomly selected 20 batteries from the production line and tested these
batteries. The tested batteries had a mean life span of 320 hours with a standard deviation of 50
hours.
a) Construct 95% confidence interval for the battery life. Assume that the battery life follows
Normal distribution.
b) Construct 99% confidence interval for the battery life. (Assumption that the battery life follows
Normal distribution is not valid).
c) Write down the hypothesis to check the claim.
d) Do we have enough evidence to suggest that the claim of an average lifetime of 350 hours is
false? (Carry out hypothesis testing to check the claim at 5% significance level). Assume that the
battery life follows Normal distribution.
e) If the assumption that the battery life follows Normal distribution cannot be made, carry out the
hypothesis testing procedure to check the claim.
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