April 1999
SA205: SYSTEMS ANALYSIS

QUESTION 1 (Compulsory)

Total Marks: 20 Marks

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GRADE A
Sample student's solutions are indicated in green.
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(a) What is the formula for the payback period, before the introduction of taxes? [1]
P = I / R

where
P = payback period.
I = investment.
R = average annual return on investment.

 
(b) Give one example of each of the following types of interview questions:
(i) Open-ended questions. [1]
(ii) Closed questions. [1]
(i) What do you think of about microcomputers for managers?
(ii) How many subordinates do you have?

 
(c) What is a Gantt chart? [2]
Gantt chart is a bar chart that shows all the activities carried out in a system project and the time schedule of each of those activities.

 
(d) List three disadvantages of the structured analysis and design methodology. [3]
  1. Too much time is spent in analysing and designing the system resulting in additional development cost.
  2. Additional retraining cost is incurred in cases where the system developers are unfamiliar with the standard system development tools.
  3. Since the system is graphically represented without an actual working model, it is very much a logical model which is abstract.

 
(e) Given the basic system model shown below, identify one area in which an improvement to this model can be made, and also state one application area in which it could be used.

pic1.gif (1857 bytes)

 

 [3]
The model can be improved by including a predictor. An example of an application area is the stockmarket system whereby the system is able to predict the trend of the market.

 
(f) Describe two situations in which you might use a decision tree. [2]
  1. When complex combinations of conditions, actions and rules are found.
  2. When it is necessary to avoid impossible situations, contradictions and redundancies.

 
(g) What is the purpose of a structured walkthrough? [1]
Strutured walkthrough is a formal meeting organised to review the system development processes with the aim of improving quality.

 
(h) Describe two potential sources for conflict which should be kept in mind when determining and evaluating system constraints. [4]
  1. Present vs Future
    Is the constraint to be met as soon as the system is developed? Is the constraint to be met at a future time? E.g.  if the system is to cater for network in the future the system should be designed in such a way to accommodate the future growth.
  2. Internal vs External
    Is the constraint set by the organisation? Is the constraint imposed by external force like government?

 
(i) Name two categories of computer-based information systems. [2]
  1. Transaction Processing System (TPS)
  2. Management Information System (MIS)