Part C

Question 1

Economically useful life

Answer 1

The period between the beginning of systems operations and the point when operational costs are rapidly increasing

Question 2

cost-benefit analysis

Answer 2

The process of comparing the anticipated costs of an information system to the anticipated benefits. Cost-benefit analysis is performed throughout the SDLC to determine the economic feasibility of an information system project and to compare alternative solutions

Question 3

Payback Analysis

Answer 3

Payback analysis is the process of determining how long it takes an information system to pay for itself. the time it takes to recover the system’s cost is called the payback period. to perform a payback analysis, the following steps are executed:
1. determine the initial development cost of the system
2. Estimate annual benefits
3. Determine annual operating costs
4. Find the payback period by comparing total development and operating costs to the accumulated value of the benefits produces by the system.

Question 4

Return on Investment (ROI)

Answer 4

(ROI) is a percentage rate that measures profitability by comparing the total net benefits (the return) received from a project of the total costs ( the investment of the project. ROI is calculated as follows:
ROI=(total benefits-total costs)/total costs

Question 5

Audit trail

Answer 5

A record of the source of each data item and when it entered a system. in addition to recording the original source, an audit trail must show how and when data is accessed or changed, and by whom. all these actions must be logged in an audit trail file and monitored carefully