# CS605 Software Engineering-II Assignment 3 Solution Fall 2013

Q.1

For two projects i.e. Project-A and Project-B, consider the following values of “Mean Time To Failure (MTTF)” and “Mean Time Between Failure (MTBF)”.

 MTTF MTBF Project-A 30 40 Project-B 25 35

Using the above information, find out that the availability of which application is high.                           10

Project A:-

Availability = (MTTF/MTBF) x 100

Availability = (30/40) x 100

Availability = 75

Project B:-

Availability = (MTTF/MTBF) x 100

Availability = (25/35) x 100

Availability = 71.42

Availability of Project A is high

Q.2 Consider the data collected during testing phases of two projects i.e. Project-A and Project-B. Determine in which case the defect removal efficiency remained high?                                                                           10

 Errors from previous stage Errors passed through Amplified errors Newly generated errors Errors passed tonextstage Testing phase of project-A 35 35 0 5 20 Testing phase of Project-B 8 8 0 5 12

Solution:

Defect removal efficiency, DRE = E / (E+D), where
• E – errors found before shipment
• D – errors found during operation

35/35+20=35/55=0.63  project A    project A defec

8/8+12=8/20=0.40  project B

Testing phase of project-A has high defect removal efficiency as the 35 errors were removed during the testing phase.