You may use FND_STAT in order to collect statistics or you may submit the 'Gather Schema Statistics' concurrent program from the front end. You may run this program to collect statistics on the products/users (eg GL, AP, AR and etc) which you have installed in your EBS or simply run it on all schemas to update the statistics for all users.
Please refer notes:
FNDNLINS.SQL: Performance Issue Running Script. (Doc ID 788008.1)
OM-PERF: Performance Tuning - FAQ (Doc ID 113573.1)
Also refer links:
Hope this helps!