# BUS 102 Arab Open University variance of The Number Stats Solved Practice

Description

Please write the solution steps in detail

BUS102
Introduction to Statistics
Final Examination – THE – Version A
2020-2021 /Second Semester/Spring 2021
Number of Exam Pages: 10
(including this cover sheet(
Time Allowed: 48 hours
Question
Number
Question 1
Question 2
Question 3
Question 4
Question 5
Total in Figures
Total in Letters
for this question
20
15
25
20
20
100
Student’s
Marker Name and Signature
Instructions
1. This examination consists of Five questions. You are required to answer all questions.
2. Keep in mind that any form of cheating will not be tolerated and will subject you to AOU
cheating policy.
BUS102/ THE-Final – Ver A
1 of 10
2020-2021/Spring
Take Home Exam for Final Assignment 2020-2021/Second
BUS102 – An Introduction to Statistics
Cut-Off Date : 5th June 2021
Cut off Time: 10:05 AM
Total Marks
Duration: 48 Hours
: 100
Contents:
Warnings and Declaration……………………………………….………………………………………………………………. 2
Question1 ……….…………………………………………………………………………………………….…………………….…. 3
Question 2 ……………………………………………………………………………………………………………….………………4
Question3 …………………………………………………………………………………………………………………………………5
Question 4 ………….…………………………………………………………………………………………………………….……….6
Question 5………………………………………………………………………………………………………………………………….7
Table Values……………………………………………………………………………………………………………………………8 – 13
Plagiarism Warning:
As per AOU rules and regulations, all students are required to submit their own THE-Final work and avoid plagiarism.
The AOU has implemented sophisticated techniques for plagiarism detection. You will be penalized for any act of
plagiarism as per the AOU’s rules and regulations.
Declaration of No Plagiarism by Student (to be signed and submitted by student with THE-Final work):
I hereby declare that this submitted THE-Final work is a result of my own efforts and I have not plagiarized
any other person’s work.
Name of Student: ————————————————————————Student ID No.—————————————————————————Signature: …………………………..…………………………………………………………………..
Section No. ———————————————————————————–Date:………………………………………………………………………………………………….…………
BUS102/ THE-Final – Ver A
2 of 10
2020-2021/Spring
Question 1: (20 points)
(A) The number of laptops sold daily at a local electronics shop has the following probability
distribution.
(10 marks)
X: # of laptops sold
P(X=x)
12
0.4
13
0.3
14
0.2
15
0.1
a) What is the mean of the number of laptops sold on a given day?
b) What is the variance of the number of laptops sold on a given day?
(B) Internet service providers (ISP) need to resolve customer problems as quickly as possible. The
probability for a customer call regarding Internet service interruption is resolved within one hour
is 70%. During one day, the company had 10 customer calls.
(10 marks)
a) What is the probability that exactly four of the customers had their problems solved?
b) What is the mean of the number of calls who had their problems solved?
c) What is the variance of the number of calls who had their problems solved?
(10 + 10 = 20 marks)
BUS102/ THE-Final – Ver A
3 of 10
2020-2021/Spring
Question 2: (15 points)
Suppose a researcher goes to a small college of 200 faculty, 12 of which have blood type Onegative. He obtains a simple random sample of n = 20 of the faculty. Let the random variable X
represent the number of faculty in the sample of size that have blood type O-negative.
(a) What is the probability that 3 of the faculty have blood type O-negative? (Round your answer
to the nearest thousandth).
(10 marks)
(b) What is the probability that a none (x = 0) of the faculty has blood type O-negative? (Round
(5 marks)
(10 + 5 = 15 marks)
BUS102/ THE-Final – Ver A
4 of 10
2020-2021/Spring
Question 3: (25 points)
(A) The replacement times for DVD players are normally distributed with a mean of 7.1 years
and a standard deviation of 1.5 years (data from Consumer Reports). What is the probability
that a randomly selected DVD player will be replaced in less than 5 years? (12 marks)
(B) In a city, it is estimated that the maximum temperature in June is normally distributed with a
mean of 23º and a standard deviation of 5°. Calculate the probability of having a maximum
temperature between 20° and 28°
(13 marks)
(12 + 13 = 25 marks)
BUS102/ THE-Final – Ver A
5 of 10
2020-2021/Spring
Question 4: (20 points)
(A) Suppose the average height of men football players follows a normal distribution with a
mean of 175 cm and a standard deviation of 20 cm. If a sample of 10 players is selected at
random, what is the probability that the sample mean is above 185 cm?
(B) A machine fills small boxes with cereal. The amount deposited into the box is normally
distributed with a mean of 24.8 ounces and a standard deviation of 0.20 ounces. If a sample of 9
boxes is chosen at random, what is the probability that the sample mean is between 24.9 and 25
ounces?
(10 + 10 = 20 marks)
BUS102/ THE-Final – Ver A
6 of 10
2020-2021/Spring
Question 5 (20 points)
(A) In a sample of 12 men the quantity of hemoglobin in the blood stream had a mean of 15 g/dl
and a standard deviation of 3 g/dl. Find the 99% confidence interval for the population mean
(B) A financial officer for a company wants to estimate the percent of accounts receivable that
are overdue. He surveys 500 accounts and finds that 350 are overdue. Find a 95% confidence
interval for the proportion of all accounts receivable that are overdue. (Round your final answers
to the nearest hundredth)
(C) Interpret the results (the intervals) you got in both the scenario given above (A and B)
(10 + 6 + 4 = 20 marks)
End of Exam Questions
BUS102/ THE-Final – Ver A
7 of 10
2020-2021/Spring
KEY FORMULAS
BUS102/ THE-Final – Ver A
8 of 10
2020-2021/Spring
Areas under the standard normal curve
BUS102
10
Page 9 of
Student’s t distribution
BUS102
10
Page 10 of