Quality is delighting customers
ok - I'm not sure but I'll give it a try:
(1) weighted defect:
When a tester finds a bug he raises a defect, which has to have different informations (Time, description, Status, unique Key, Environment description, ... and so on). One of the most important things is the "Priority"/ "Severity" (from critical to nice to have). From now on the defect has a "weight" which allows you to prioritize.
Normally you calculate the degect density to be able to make a statement about "From which part of the software do most of the bugs come from?" Are the bugs normally distributed (gaussian) all over the software? Or do they cumulate at interface A?
defect rejection ratio:
I dont really have an idea what this could be? Maybe the ration of Issues that are rejected by the development team? To get to know the number of Issues, raised by the testteam, which were no bugs (mistake from the tester)? Or to get to know the number of Issues that were rejected by the devolpers because of a lack of information from the testers?
The Measure Defect-Density (DD) Measures the number of defects in a
perticular size of code. it is measured as follows: LOC (Lines of Code),
Defects: number of defects in the code; DD = Defects/(K)LOC
defect rejection ratio: Its the ration of no.of bugs posted/the no.of bugs rejected.
This is just a way to check on average, for how many (valid) bugs a rejected bug exist.
Defect Density is used to estimate the number of defects we will find depending upon the history of the application under test.
As rightly said it can be measused by defects/KLOC also Defects / iteration or numbe of test cycles/rounds performed.
Both are also used to easure productivity
Defect Density - Developer
Defect Rejection ratio - Tester
defect density is defined as ratio of number of defects detected in a component (or system) to the size of the component or sysytem...(size is measured in terms of LOC,FP)
DD=number of defects/LOC
When the product 's reliabilty is much concerned DD is very much useful..
....If the ratio falls below a threshold,then the product may be deemed to have met the defect density exit criteria...