My gm is doing the epic fantasy for our stats, I was wondering if theres a chat tjat goes below 7, the chat in core rule book goes from 7 - 18 just curious if there more to it or a equation for it
Here is a link to the ability score section on d20pfsrd.com.
When using a "purchase" method like Epic Fantasy - 25pts, you cannot purchase a score higher than 18 or lower a score to anything below 7.
That being said, your racial modifiers can lower a score below 7, when applied.
Example:
Say you choose to be a Dwarf, they get a -2 CHA, +2 WIS, +2 CON.
So, you could lower your CHA to a 7, then apply the -2 to take it to a 5.
Note that you'll only get the extra points for lowering it to 7, you don't get more extra points from the racial modifier taking your CHA to 5.
Likewise, you could buy a CON of 18, then add the +2 to get a CON of 20.
Yes, the Table: Ability Modifiers and Bonus Spells covers it (also here). Basically, the modifier changes by 1 at every even number.
There is a formula, yes. Every two points up or down adjusts your stat modifier by one point, so if you have a strength of 5, you have a -3 modifier, a strength of 3 gives you a -4 modifier, and a strength of 1 gives you a -5 modifier.
There's no point buy equivalent for abilities below 7, however. If you're using point buy, 10 in any ability is the default and costs 0 points.
The reason for this is that it's too easily abused if you allow characters to take arbitrarily low stats. I could, for example, take a cleric with a 3 intelligence in order to pump my wisdom and my physical attributes to amazing levels, but this would probably result in a eggshell-with-hammer type of character. She would be unbalancingly good within her narrow speciality and unbelievably fragile outside of it.
It makes the game generally less fun for everyone. There is a lot of discussion on the board suggesting that even a statistic of 7 is somewhat munchkin-ish.