I assume you mean the default spamlevel which is 5.
yes, just go the Mail Filter/What/Spam Object and change the value from 5 to the new value.
you can also build new rules, for example you can define rules which block emails with spam level 10 or higher, quarantine spam between 5 and 10, mark spam as possible spam between 3 and 5.
for such configuration take a look into the deployment guide, sample rules