Hello, this is my first time posting, I have been playing Arena and I am liking it a lot, but does anyone know what are the stat modifiers for the classes and races?

To the best of my knowledge, none of the classes modify your statistics: that was something that wasn't added until Morrowind. As for the races, I believe they simply gain +5 to each of the statistics their description mentions, but I COULD be wrong on that.

Argonians do not tire easily while swimming, and seldom drown. They can also swim faster than any other race. They are adept in any art involving the arcane, or involving thieving and sleight of hand.
Bretons take half damage on any Magic based attack, and no damage on a successful save. They are excellent in all the arcane arts.
Dark Elves receive their (level / 4) as a bonus to hit and damage with any melee or ranged weapon. They are adept in any art involving the blade and shield combined with the arcane arts.
High Elves seem drawn to magic as a moth is to flame. They have a natural affinity to its use, and often make quite formidable wizards. High Elves are naturally immune to paralyzation. They are adept in any art involving the arcane.
Khajiit are expert climbers, able to scale chasm wall sides with speed unmatched by any other race. They are adept at all arts involving thieving and sleight of hand.
Nords take half damage from Cold based attacks, and on a successful saving throw take no damage. They are excellent in all arts concerning the blade and shield.
Redguards receive their (level / 3) as a bonus to hit and damage with any melee weapon (ie…excluding bows). They are excellent in all arts concerning the blade and shield.
Wood Elves receive their (level / 3) as a bonus to hit and damage with any bow weapon. They are well suited towards any class, although their nimbleness serves them best in any art involving thievery.

Taken from UESP.net