[Question] How are Pokemon Base stats calculated?

hello, before some days i've openned a thread and asked how to caculate pokemon damage, its work.
now i need to caculate base stats, i got it like that (for example):
Bulbasaur
45,49,49,45,65,65
what's 45? hp? which level?
how can i caculate it?
thannk you very much =]

Bulbapedia explains it all.

HP is a stat just like Attack. The 45 is the base HP stat, and is used in a calculation to determine the actual HP amount.

thannks =]
more one question, in bulbpedia in the gen III formula (i cant show images right now, i need 15 posts), so in the formula there is EV\4, and IV +... whats IV and EV means?
thannks again! =)

Again, Bulbapedia explains it all: IVs and EVs.

thannks, i have no energy to do the IV and EV treats in my game -__-
i did 4 as IV and 1 as EV and it's sucsess (i checked it on pokemon stat caculator and it's work).
Thx for you both!! :)