1Answer :If you are really sure its a major bug, You  try 
to convince the developer by reproducing the bug & sending 
screen shots...If it doesnt help, You talk to ur team lead 
or bring up that issue in Team meetings...

1:-once again we will check that condition wid all reasons. 
Then we will attach screen shots with strong reasons. Then 
we will explain to the project manager and also explain to 
the client when they contact us Sometimes bug is not 
reproducible it is because of different environment suppose 
development team using other environment and you are using 
different environment at this situation there is chance of 
bug not reproducing. At this situation please check the 
environment in the base line documents that is functional 
documents if the environment which we r using is correct we 
will raise it as defect We will take screen shots and sends 
them with test procedure also.

2:-Cost of software quality is related to customer 
satisfaction that is useful to enable our understanding of 
the cost involved in delivering good-quality software.  Itz 
adaptation to software offers the promise of preventing 
poor quality. The degree to which customers or users 
perceive that a software product meets their composite 
needs and expectations. Software product has value for its 
various stakeholders relative to the competitive 
environment. Software product possesses a combination of 
desired properties, e.g., reliability, portability, 
maintainability. And itz depend upon convey quality of 
product which required customer satisfaction.
3:-Software root cause analysis is process to 
systematically categorize and analizye and identified 
defect of software development process. these defect can be 
either pre-release or post release or both. with this 
analysis root cause of significant issue are idenfied along 
with corresponding intervition to improve the software 
development process.....Thanx ...