Response time of an web site means how much time will be required to respond any request from the server to client that count as a response time of an web site.
Response time is differ to differ of all web site, its totally configuration of hardware, app , technology etc.
Let me know if you have any query. mail to me at firstname.lastname@example.org
this is related to performance criteria, I mean performance engg......................
if you want to calculate it then try to use a tool from Firefox called as Firebug and see how do they get response time for each page. there are other methods also but this would be better to understand and to atleast give you a start .
first i dont understand what is responce time of an application are you asking for results throwing application or responce time of behaviour of application, can you shoot you question some what clearly, if it is responce of browser then the following will be answer.
the responce time of web sote is depends upon the performance of you machine and speed of your internet connection as 256 kb/512 kb/1 mb like this, depends upon these the responce time will count
responce time is differ from one browser to another