oracel big parition table analyze question

our customer ask three quesiton , db is oracle 9i :

1.they have some big partition table , about 100 million  record  table ,

they said  they want to analyze this table, they find it cosumer a lot of time 5-6 hour ,

they want  to when meet this big partition table ,how to analyze it to save time ,

our colleague said thay just analyze 10% sample, i am not sure is that right or another method ?

2.and they did  analyze  table like that

analyze  table INF_IDLE_PROD_CONFIG compute statistics;

run about 5-6 hour ,and then they check user_table column num_rows ,it did't update ,