Mathematics
PMAN 635 University of Maryland Global Campus Quantitative Methods Midterm Exam

PMAN 635

University of Maryland Global Campus

PMAN

Question Description

I’m trying to study for my Statistics course and I need some help to understand this question.

Please see the attached midterm exam for Quantitative Methods

Please show all calculations in Excel.

Instructions are provided in the attachment

Unformatted Attachment Preview

University of Maryland University College ITEC 626 Mid-Term Examination 1. The layer of operation and justification are identified below. No Item Operation Layer of the OSI Model Justification 1.a Repeaters and hubs Physical Layer Both repeaters and hubs function as links and cable connectors to all devices connected. Secondly, the physical layer includes the physical and electrical requirements for data transmission through cables. 1.b Routers Network Layer Routers connect networks, and the OSI Model layer that supports data processing and transmission is the network layer. After processing, it uses routers to transmit it from one node to another over the network. 1.c FTP Transport Layer The file transfer protocol (FTP) is an online file transmission method, and thus, it is applicable in the transport layer where transmission occurs in the OSI Model. 1.d SMTP Application Layer The simple mail transfer protocol (SMTP) is an electronic mail communication protocol. Since in the OSI model, all the communication happens in the application layer, then SMTP is no exception. 1.e JPG Presentation Layer The presentation layer is tasked with determining the format of data before it is offered to the application layer for transmission. The JPG protocols ensure that images are in the right presentation format. 1.f IP Network Layer As mentioned earlier, data is transmitted over the network, and internet protocol is a data transfer method. Therefore, it works on the network layer. It delivers data packets through ordered addressing strategies. 1.g Flow control Sessions Layer The Sessions layer is designed to define how data conversations occur and how they are controlled. It also manages messages conversations and creates feedback if messages bounce. 1.h Encryption Presentation Layer Before data is transmitted from the source to the destination, it has to be protected from unauthorized access. The presentation layer is tasked with the role of encryption at the source side and decryption at the destination. Additionally, it supports the application layer, which is used to communicate and display the message to the end-user. 1.i Error detection and recovery Transport Layer Before packets are transmitted over the network, it has to be ordered and reassembled, and the work of transmission is done by the transport layer. If data is found to be broken, the layer performs recovery for transmission over the network connections. 1.j Formatting of application data Presentation Layer Formatting of application data is done at the presentation layer because it is the translator between the application and network layers. The syntax of data must be checked before transmission over the application layer (Mitchell, 2018). 2. Standard features of Ethernet and WLAN. • • • Both use the IEEE 802 standards with similar reliability levels. Both are network infrastructures used for communication and data transfer over networked devices. WLAN and Ethernet use the Carrier-Sense Multiple Access mechanisms to detect and avoid a collision in the network. Differences between Ethernet and WLAN Ethernet WLAN It is based on the IEEE standards family 802.3 They operate on the family 802.11 of IEEE. Uses electric signals for physical connection. Utilizes high energy radiofrequency; thus, no physical connection is needed. The network uses a full-duplex mechanism for transmission The networks use a half-duplex mechanism for transmission. The networks use CSMA/CD to detect network collisions. They use CSMA/CA to avert network collisions. 3. a. Frequency Modulation – refers to the method of encoding data or information in a wave carrier for transmission through changing the frequency of the wave instantaneously. Advantages of Frequency Modulation (FM) ▪ ▪ ▪ Resilient to noise – audio output is not affected during transmission. It is possible to apply low power to the transmitter – there is no need to increase the power during transmission. One can use RF amplifiers in the market. Disadvantages of Frequency Modulation (FM) o Poor spectral efficiency for different formats. o It uses a complex demodulator. 3. b. Amplitude Modulation – it is described as a modulation method where the signal strength of the carrier wave is varied in proportion to the transmitted message signal. Advantages of using the Amplitude Modulation (AM) ❖ Easy to implement. ❖ Cheap signal receivers Disadvantages of using the Amplitude Modulation (AM) ❖ Inefficient use of power. ❖ Poor bandwidth usage. ❖ Susceptible to high noise levels. 3. c. Phase Modulation – is viewed as the process of varying the phase of the carrier wave through vibrations of the source of the sound while keeping the frequency of the wave carrier fixed. Advantages of using the Phase Modulation (PM) ➢ It is simple ➢ High immunity against noise ➢ It permits high-speed communication between computers using a telephone system. Disadvantages of using the Phase Modulation ➢ Modulation requires two signals by space variation between waves. ➢ The method requires complex hardware. ➢ There is phase ambiguity. 3. d. Pulse Modulation – it refers to the procedure of converting the wave carrier into a series of spaced pulses with a constant amplitude. Advantages of using the Pulse Modulation ➢ ➢ ➢ ➢ ➢ Efficient data transmission. It is easy to separate the noise from the signal. Constant power output. Requires less power Less noise interference as the amplitude is held constant. Disadvantages of using the Pulse Modulation ➢ ➢ ➢ ➢ 4. Requires large bandwidth. It has a complicated implementation procedure. It is profoundly affected by multi-pathway interference. Both devices have to be synchronized (Hub, 2015). The telephone networks have evolved from a circuit-switched network to a packetswitched system due to societal needs, increased user numbers, technological advancements, and communications. Additionally, the evolvement is due to the need for greater efficiency and lowered costs. Circuit-switched networks were designed for voice communications and are used by the Public Switched Telephone Network (PSTN). The circuit switching connection is physically orientated and provides a dedicated, physical contact between the message source and receiver from the time connection is initiated to when it ends. It is implemented at the Physical layer, and a dedicated channel must be re-established. The data (voice) is then transferred through a predetermined path/order and utilizes the full bandwidth of the significant line. While circuit-switched networks increase reliability, it can also cause delays due to the unavailability of channels and higher costs associated with dedicate connections and strained bandwidth. Packet-switched networks are more efficient for data, and they do not require a preestablished connection, increasing the availability of bandwidth, respect, and channels. In packet switching, data is divided into packets that are assigned a source and destination address. These packets route themselves to their destination using the most efficient route based on circuit availability and then reassembles the original data. Packet switching occurs at the Network layer and can use a datagram or virtual circuit approach to determine how the packets will arrive at the destination. 5. TCP stands for Transmission Control Protocol, and UDP stands for User Datagram Protocol. Both are transportation protocols, and they operate in the transport layer. They are commonly used for sending packets over the Internet. The contrast between the two contracts is as shown below. The contrast of TCP and UDP TCP 1 Slow and reliable UDP 1 It is fast and unreliable 2 3 4 It is a connection-oriented protocol TCP is stream-oriented, preserves order, and manages flow in data transmission. Use numbered packets to check errors and to track communication. Protocol Application a. b. c. d. e. 2 It is a connectionless protocol 3 UDP does not manage data flow in transmission. 4 UDP has no mechanisms to trace packet transmission. Live video stream – use the UDP Protocol. Email – use the TCP Protocol. Satellite pictures – utilize the UDP. Tax data – employ the TCP protocol. Online gaming – the suitable protocol is UDP. 6. a. The Domain Name System (DNS) is a critical network protocol that converts hierarchical text names that are human-friendly, to IP addresses. It is distributed, maintaining its servers to translate titles and store DNS cache. DNS eliminates the need for users to remember actual IP addresses and functions similar to a phonebook of the Internet, and is crucial, as it serves as a digital identity. Therefore, security issues that create DNS risks must be mitigated, especially with malware and cyber threats increase. Some significant risks include registrar hijacking and cache poisoning. Registrar hijacking occurs when hackers take control of the domain by hacking passwords or registrars. Hackers can also use cache poisoning, by redirecting users through fraudulent addresses in the DNS servers where DNS data is cached. 6. b. Dynamic Host Configuration Protocol (DHCP) is the mechanism by which hosts are assigned IP addresses. Security is essential to protect the DHCP server from unauthorized access to IP addresses. Not protecting access points or the network can lead to security risks to the DHCP server can result in denial-of-service attacks, in which access to legitimate IP addresses are denied due to all available IP addresses being used up (Rouse, 2015). 6. c. Internet Control Message Protocol (ICMP) is an error reporting protocol that network devices use to generate and communicate error messages when IP packets cannot be delivered due to network problems (Rouse, 2015). Security issues of the ICMP can result in numerous risks including ICMP tunneling, in which covert channels that are not controlled by security mechanisms are formed between the client and server using echo requests and reply packets; and Smurf attacks in which source addresses of ICMP packets are spoofed, and broadcast is sent to all computers to congest the network. 7. Extensible Markup Language (XML) and Simple Object Access Protocol (SOAP) enable applications developed through different programming languages to exchange information and reduce interoperability issues. Extensible Markup Language (XML) is a markup language that is self-descriptive and designed to store and transport data over the Internet. It contains sender and receiver information, a header, and a message in the body. Web applications use XML to tag the data, and SOAP is used to transfer the message. SOA is a messaging protocol used to send and receive XML-based messages between applications. 8. Relational Database (RDB) and Object Database (ODB) systems both store data in an organized structure but uses varying approaches to do so. RDB stores data and the relationship between the data in tabular form, which consists of rows that contain primary keys and columns with unique names. Data in RDB is represented by files, records, and fields, and further stores relationships between the data within the columns. It is simple and can only store the data. OBD stores data as objects and is capable of storing a variety of data types, as well as methods that can be reused and provide faster access. It is also able to store unstructured data efficiently. 9. Big data provides opportunities for businesses to better their decision-making processes and operations to develop better strategies to meet their objectives and goals. Big data are large data sets that include both structured and unstructured data that can be mined for insight. Similarly, big data can contribute to network management operations. Information that is collected from various points across the network can be used to optimize network operations. Big data can help to map correlations between network problems and typical timelines of events, helping to pinpoint network related issues. It also helps in root cause analysis, enabling identification of network problems that impact the system, and then tracing the data back to the source or related events. Another benefit is that big data can help establish a baseline for normal network conditions, which helps to alert when situations arise that are abnormal and needs attention. 10. Service-Oriented Architecture (SOA) and cloud computing both offer scalability and agility, and interoperability, with reduced costs. However, SOA is more an application architecture providing horizontal services, as opposed to cloud computing, which aligns with an IT architecture with vertical services. SOA is an architectural approach that organizes system components based on the service it provides and provides a collection of services according to business functionality. SOA services are well-defined, selfcontained, functional, and reusable. It uses loose coupling, allowing services to operate independently from the platform and enabling businesses to extend or upgrade existing facilities. The benefits of SOA include improved interoperability, flexibility, and reliability. It also decreases the costs associated with software development and management expenses. Another great benefit of SOA is that it reduces the time to market by enabling quicker development, with improved performance and functionality. In cloud computing, virtualized software, infrastructure, and platforms are provisioned by the cloud service provider through the Internet. This allows businesses to access unlimited resources that are scalable based on needs and changing demands. It provides greater accessibility and interoperability while reducing hardware and maintenance costs. However, the quality of service and security is dependent on the capabilities of the service provider, and businesses must rely on the service provider’s ability to safeguard and secure their data. References Mitchell, B. (2018). The layers of the OSI model illustrated. Life Wire. Retrieved from https://www.lifewire.com/layers-of-the-osi-model-illustrated-818017 Electronics Hub. (2015). Modulation and different types of modulation. Retrieved from https://www.electronicshub.org/modulation-and-different-types-of-modulation/ Rouse, M. (2015). ICMP (Internet Control Message Protocol). Tech Target. Retrieved from https://searchnetworking.techtarget.com/definition/ICMP PMAN635- Spring 2020 Session 7 - PMAN635 Mid-Term Exam Name: (Your name goes here) Please answer any ten of the twelve questions. Each question is weighted equally. If you answer more than ten questions, I will select the best ten. Note that the highest grade you can receive is 100 points. In addition to posting this answer sheet, be sure to post an excel file that shows your calculations. If you chose a problem that requires CB, you must post the file that includes your assumptions, forecast and the results of your simulations. Post any MS Project file you used to answer a question. DO NOT just insert MS Project, Excel or CB derived answers in your answer sheet. 1. Two investments (A and B, below) have been proposed to the Capital Investment committee of your organization; a. The required rate of return for your company is 15%. What is the NPV for each investment? Assume the initial investments ($150k and $50k) occur at the beginning of the year and all other costs and benefits occur at the end of the year indicated. Ignore inflation. b. What is the payback period for each investment? c. Which investment would you recommend and why? d. Why might you recommend the other investment? Investment A Costs: Benefits: Year 1 $150,000 - Year 1 $5,000 $75,000 Year 2 $5,000 $55,000 Year 3 $5,000 $35,000 Year 4 $5,000 $20,000 Year 5 $5,000 $65,000 Investment B Costs: Benefits: Year 1 $50,000 Year 1 Year 2 Year 3 Year 4 Year 5 $30,000 $15,000 $10,000 $10,000 $15,000 2. Using the forward and backward pass method, identify the Critical Path and total duration for the following network. Show all work. Task a b c d e f Duration 5 10 10 5 3 10 Predecessor a a b c d, e PMAN635- Spring 2020 3. For the network below: a. Calculate T-E and Variance for each activity. Assume the durations have 95% certainty (i.e. the range from optimistic to pessimistic durations covers 95% of all possible durations). b. Calculate the expected duration of the network. Do not use Crystal Ball. c. What is the probability the network will take no more than 23 days? Use the Ztable or Excel’s NORM.DIST formula, not Crystal Ball. Be sure to show all work. Task Optimistic Duration A B C D 8 4 8 3 Most Likely duration 10 5 8 3 Pessimistic Duration 14 7 9 3 T-E Var Pred A A B, C 4. You are still trying to get your engineering cost estimate for the Kuraiz-Reconda Fiber Optic Cable (KRFOC) project approved by your sponsor (remember IA-5?). In opening your morning mail, however, you see a proposal from Engineers ‘R Us to do all the KRFOC engineering for a fixed price of $60,000. Comparing that with your estimate of doing the work yourself (See the IA-5 question 2b School Solution): a. What is the probability that the price for completing the work yourself will be less than the Engineers ‘R Us offer? Show all work. b. Would you recommend the work be done in-house or accept the fixed price offer from Engineers ‘R Us? Why or why not? Be sure to provide all calculations. 5. Which of the following are activities and which are work packages? a. b. c. d. Project Plan Prepare the purchase order for a router System Design Package Install the foundation 6. Please answer each of the following: a. What is the expected time to complete a task with an optimistic (a), most likely (m), and pessimistic (b) times of 2, 4 and 7 days respectively? b. What is the standard deviation of the same task, assuming that 99.7% of the outcomes fall between a and b? c. What is the standard deviation of the same task, assuming that 90% of the outcomes fall between a and b? PMAN635- Spring 2020 7. There are three (and only three) paths through a network (project), each with a probability of completion in less than 24 months as indicated: • S- a-b-F P1(<24) = .80 • S- d-e-F P2(<24) = .80 • S- g-h-F P3(<24) = .80 d. If the tasks are independent, what is the probability of the project being completed within 24 months? Note: S is the start node, F is the finish node e. What is the probability the project being completed in 24 months or longer? 8. Match each of the following activities with one of the five project management process groups (initiating; planning; execution; monitoring and control; closing). f. You are preparing the monthly project status report. g. You are completing formal transfer of the product developed by your project team to the customer. h. Your project sponsor is reviewing the list you prepared of the functional managers and other stakeholders who might be affected by your project. Once approved, you will publish this as a part of your stakeholder management plan. i. The installation team is completing all as-built drawings. 9. Which of the following statements are true and which are false: j. A discrete activity is one which does not provide a definitive end product and is measured by the passage of time. k. To account for the risk of predicting future profits, you would decrease the relative variance for those profits the further from your baseline year that they are. l. An activity’s float is the amount of time its start time or duration can be extended without affecting the start of the next task. m. Slack is a term coined by Professor Hall to indicate that a student ought to wake up and get this exam posted! 10. Answer one of the two following questions: n. Name one thing you have learned so far this semester and how you might apply it if assigned to a project in your organization. o. You ...
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Final Answer

I attached the excel work for Q1,2 and 3.Rest are done in the docs.Pleasure working with you.Let me know for any clarifications.Good Bye.

Investment A
Cost
Benefits
Netcash flow
Present value
Required rate of return
Balance

Investment B
Cost
Benefits
Netcash flow
Required rate of return
Balance

Year 1
Year 1
Year 2
Year 3
150000
5000
5000
5000
75000
55000
35000
-150000
70000
50000
30000
60869.57 37807.18 19725.49
15%
150000

80000

30000

0

Year 1
Year 1
Year 2
Year 3
50000
30000
15000
10000
-50000
30000
15000
10000
15%
50000

20000

5000

-5000

NPV
Year 4
Year 5
5000
5000
20000
65000
15000
60000
8576.299 29830.6

-15000

Year 4

-75000

Year 5

10000
10000

15000
15000

-15000

-30000

A.
B

$ 6,809.14
$ 7,179.46

Payback Period
3
2.5

Project Management
Data
Activity
Activity
b
c
Data
e
f

Precedences; 1 time estimate

Gantt Chart
Activity

Immediate Predecessors (1 per column)
Pred 1
Pred 2

Time

5
10
10
5
3
10 d

b

a
a
b
c
e

c
Data
e

Results
Activity
Activity
b
c
Data
e
f

f
Early Start Early Finish Late Start Late Finish Slack
0
5
18
23
0
10
8
18
0
10
0
10
10
1...

psumanrec (4252)
Cornell University

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