GM03 Business Statistics

GM03
Business Statistics
Assignment - I
Last Date of Submission: 15th October 2014
Maximum Marks: 100
Assignment Code: 2014GM03B1
Attempt all the questions. All the questions are compulsory and carry equal marks.
Section-A
1.
Prof. Hardtack gave four Friday quizzes last semester in his 10-student senior tax
accounting class as follows:
Quiz 1
Quiz 2
Quiz 3
Quiz 4
60
65
66
10
60
65
67
49
60
65
70
70
60
65
71
80
71
70
72
85
73
74
72
88
74
79
74
90
75
79
74
93
88
79
95
97
99
79
99
98
a)
Find the mean, median, mode for each quiz.
b)
Based on the results obtained in (a) above, indicate the measure of central
tendency you would like to use for each of the quizzes with reasons.
2.
A biometric security devise using fingerprints erroneously refuses to admit 1 in 1000
authorized persons from a facility containing classified information. The device will
erroneously admit 1 in 10,00,000 unauthorized persons. Assume that 95% of those who
seek access are authorized. If the alarm goes off and a person is refused admission,
what is the probability that really authorized?
3.
Suppose the waiting time to get food after placing an order at a fast-food restaurant is
exponentially distributed with a mean of 60 seconds. If a randomly selected customer
orders food at the restaurant, what is the probability that the customer will have to wait
at least two minutes?
4.
A family has two children – one male child and the other a female child. Both the
children are grown up and their daily expenditure is believed to be normally distributed
with a mean of Rs.80 and Rs.60 for the male and the female child with standard
deviation of Rs.20 and Rs.10 respectively. Find the probability that the two child
together have an expenditure of more than Rs. 160.
GM03/July 2014
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Section-B
Case Study
A car manufacturer who is producing cars at the rate of 4000 cars a month requires to procure
ignition equipment from vendors. The company has a policy of placing orders for 12000 ignition
equipment every time they order. The vendor has indicated that 3 % of the ignition equipment
is likely to be faulty in each shipment. Since it is not possible to test each and every ignition
equipment by the car manufacturer, the manufacturer decides to randomly sample 200 ignition
equipment and if more than 2 of them are found to be defective the entire batch of order shall
be returned back.
Case Questions:
a)
What sampling method would you suggest for the car manufacturer?
b)
What is the probability that the batch will be returned back to the vendor.
GM03/July 2014
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GM03
Business Statistics
Assignment - II
Assignment Code: 2014GM03B2
Last Date of Submission: 15th November 2014
Maximum Marks: 100
Attempt all the questions. All the questions are compulsory and carry equal marks.
Section-A
1.
Last year television stations WXYZ’s share of the 11pm news audience was
approximately equal to 25%. The station’s management believes that the current
audience share is higher than last years 25% figure. In an attempt to substantiate this
belief, the station surveyed 400 11pm viewers and found that 146 watched WXYZ. Set
up the null and alternative hypothesis and test the same at 5% level of significance.
What is your conclusion?
2.
A retailer that sells home entertainment systems accumulated 10451 sales invoices
during the previous year. The total of the sales amount on these invoices as claimed by
the company is Rs.63,84,675. In order to estimate the true total sales for last year, an
independent auditor randomly selects 350 of the invoices and determines the actual
sales amounts by contacting the purchasers. The mean and standard deviation of the
350 samples sales amounts are Rs. 532 and standard deviation 168. Find the point and
interval estimate given that a 95% confidence is required. Do you think that the sales
invoice claimed by the company are correct?
3.
One of the questions on the Business Week subscriber study was, “In the past 12
months when travelling for business, what type of airline ticket did you purchase most
often”. The data obtained are shown in the following table.
Type of Flight
Type of Ticket
Domestic flights International flights
First Class
29
22
Business / Executive class
95
121
Full fare economy /coach class 518
135
Based on the above can it be concluded that type of ticket is dependent on the type of
flight taken. Use 5% level of significance.
GM03/July 2014
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4.
To study the effect of temperature on yield in a chemical process, five batches were
produced at each of three temperature levels. The results follow. Construct an analysis
of variance table. Use a 5% level of significance to test whether the temperature level
has an effect on the mean yield of the process.
Yield
Temperature
50degC
34 24 36 39 32
60degC
30 31 34 23 27
70degC
23 28 28 30 31
SECTION-B
Case Study
A research project was undertaken to determine if there is a relationship between the years of
experience on the job (A) and efficiency rating of employees (B). The objective of the study was
to predict the efficiency rating of the employee. The sample results are as follows:
Years of Job (A)
1 20 6 8 2 1 14 8 4 6
Efficiency rating (B) 6 5 3 5 2 2 4 3 3 4
a)
Which variable is the dependent variable?
b)
Find if there is correlation between the two variables and test the correlation
coefficient. (use 5% level of type I error)
c)
Estimate the linear regression model. Do you think that the regression coefficient would
be significant at 5% level of significance? Give reasons.
d)
Do you think the overall regression model would be significant? Give reasons.
GM03/July 2014
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