1.2 Analysis Q Flashcards
Purpose of systems analysis
Investigate problems with the current system and establish the user requirements.
Involves fact finding techniques such as Interviews Questionnaires Document sampling Observation
Compare and contrast interviews and questionnaires as fact finding techniques
Both involve feedback from user to find problems with system.
Interviews are hard to quantify.
Questionnaires have low response rate.
Interviews are one on one.
Questionnaires involve a representative group.
Follow up questions can be asked with interviews.
Interviews can obtain more detailed feedback.
Interviews can contain leading questions.
How observation can be used during fact finding.
Analyst observed users as they carry out their tasks. Allows analyst to see directly what each user does.
How interviews can be used during fact finding.
The representative users answer questions from the system analyst on a one to one basis.
User can express their opinions in a detailed way.
How questionnaires can be used during fact finding.
A representative group of users who complete a set of pre determined questions to identify current data processes.
Evaluate interview
Users answer questions from the analyst on one to one basis.
Advantages
Follow up questions can be asked. They gather detailed opinions.
Dosadvabtages.
Time consuming.
Temptation to use leading questions to get answers analyst wants.
Hard to quantify.
Evaluate questionAire
Users complete a set of pre determined questions to identify current data processes.
Advantages
Easy to quantify
Disadvantages
Less detailed answers.
Can’t ask follow up questions.
Response rate may be low.
Evaluate observation
Analyst observes users as they carry out their tasks.
Advantages
See directly what each user does.
Can gain more insight into the systems strengths and weaknesses.
Disadvantages.
Users may respond differently when being observed.
Evaluate document sampling
The analyst inspects documents to get a better idea of the inputs and outputs of the current system.
Advantages
Can see the volume of data the system handles.
Disadvantages
May be time consuming
By referring to the stock control example. Explain what is meant by functional and non functional requirements.
Functional user requirements specify what activities the system must be able to do.
In this case. Deduct one from stock as each product is sold.
Non functional requirements go beyond the users immediate needs to include extra capabilities and criteria for judging the new system.
In this case. Stock level should be updated within 3 seconds of an item being sold.
Functional and non functional in payroll system.
Functional in this case. Allow input of hours worked for each employee.
Non functional. Allow some users different levels of access.
Functional and non functional in billing example.
Functional- print receipt.
Non- don’t allow sale staff to change prices.
Explain purpose of level 0 DFD
Sees system as one main process. Identifying the main data source and the main flows into and out of this process.
Explain purpose of level 1 DFD
Breaks down process into sub processes and showing how data flows between these.
Compare and contrast level 0 and level 1
Both contain data source. Data flow and processes.
Only a level 1 has data stores.
