THEORY EXAMINATION (SEM–VI) 2016-17 SOFTWARE QUALITY ENGINEERING

SOFTWARE QUALITY ENGINEERING (EIT061)

Section-wise Solved Answers & Notes

SECTION – A (10 × 2 = 20 Marks)

Very short & precise answers

(a) Types of software reviews

• Management review – progress & planning   • Technical review – design & code correctness
• Inspection – formal defect detection                • Walkthrough – author explains work to team

(b) Function points

Function Points measure software size based on functionality delivered to the user, independent of programming language.

(c) Hierarchical model of quality

It represents software quality in levels, where high-level quality factors are broken into criteria and metrics.

(d) Requirements of customer problem metrics

• Easy to understand                                            • Customer-oriented
• Measurable                                                        • Relevant to quality goals

(e) Phase-based Defect Removal Pattern

It shows how defects are introduced and removed in different SDLC phases like requirement, design, coding, and testing.

(f) Fix quality vs Software quality

(g) Backlog & Management Index

• Backlog: Pending defects yet to be fixed
• Management Index: Ratio of fixed defects to reported defects in a time period

(h) Software measurement

Software measurement is the process of assigning numbers or symbols to attributes of software for assessment and control.

(i) Statistical Software Quality Assurance (SSQA)

SSQA uses statistical techniques to monitor defects, failure rates, and process performance.

(j) Static & dynamic testing tools

• Static tools: Code analyzers, linters
• Dynamic tools: Test execution tools, performance testing tools

SECTION – B (Attempt Any Five) (5 × 10 = 50 Marks)

(a) McCall’s Quality Model

McCall’s model classifies quality into three perspectives:

Product Operation – correctness, reliability, efficiency, integrity, usability

Product Revision – maintainability, flexibility, testability

Product Transition – portability, reusability, interoperability

Example:
Reliability → failure frequency
Maintainability → mean time to repair

(b) Defect arrival & phase-based removal pattern

• Defects increase during coding phase          • Most defects should be removed during early phases
• Late defect removal increases cost

Graph:                                                               Defect arrival vs time shows peak during testing.

(c) Software maintenance metrics                     • MTTR (Mean Time To Repair)
• Change request rate                                     • Defect backlog

Example:                                                            Higher MTTR → poor maintainability

(d) Reliability growth model

Shows improvement of reliability over time as defects are removed.

Types:                                                                • Exponential model
• Logarithmic model                                           • Delayed S-shaped model

(e) Why quality estimation is required?

• Predict product quality                                     • Control cost & schedule
• Reduce risk

Quality estimation helps estimate project cost by predicting defect density and rework effort.

(f) Characteristics of modern testing tools

• Automation support                                         • Regression testing
• Reporting & analytics                                       • Integration with CI/CD
• Reusability

(g) SQE terms

(i) Mean Time To Failure (MTTF):                    Average operational time before failure.

(ii) Defect density:

Defect Density=Number of DefectsSize of Software\text{Defect Density} = \frac{\text{Number of Defects}}{\text{Size of Software}}Defect Density=Size of SoftwareNumber of Defects​ 

(h) Quality planning & control

Quality planning:       Defines quality goals, standards, and processes.

Quality control:          Monitors results and takes corrective actions.

Example: Code reviews to control defect leakage.

SECTION – C (Attempt Any Two) (2 × 15 = 30 Marks)

Q3. Delayed S-Shaped Reliability Growth Model

This model assumes:                                           • Slow defect detection initially
• Rapid defect removal in middle                       • Slow improvement at later stage

Graph:   Failure rate vs time shows S-shape curve.

Use:       Used when testing starts late or learning curve exists.

Q4. Short Notes

(i) Quality standards & processes

• ISO 9001                                                            • CMMI
• Define procedures, audits, and documentation

(ii) Total Quality Management (TQM)

TQM focuses on continuous improvement, customer satisfaction, and involvement of all employees.

(iii) Major SQA activities

• Process definition                                              • Audits & reviews
• Metrics collection                                              • Testing support
• Documentation control

Q5.

(i) Software verification & validation

(ii) Static & dynamic testing tools

Static:
• Code review tools                                               • Static analyzers

Dynamic:
• Unit testing tools                                                • Performance testing tools

(iii) Proof of correctness

A mathematical technique used to prove that an algorithm or program satisfies its specification.