Hi 

90% means 90th person response time out of 100. 90 
percentile response time is the 
90th response time u can see this values in reports..


when generate the report we can see 90% means Ex One 
scripts we have 10 start and end transaction and i ran this 
test for 20 users so each user taking time Transaction 
responce time is defarent...

One Transaction (1)...ex : Navigation to_ Inbox Page 
1 users 20Sec 
2 users 78 
3 user 45
4 user 04 
5 user 12
6 user 15
7 user 25
8 user 45
9 user 12
10 user 72

this 90% means which users taking more time out of this 10 
users 72 Sec it's called 90% ...not 78% (it's Called Max)