Distribution help please. =[

I can't figure this problem out. I left my maths book at school so I no longer have the formulas. :[

Q6. The mass of baby guinea pigs four days after birth is a normally distributed variable with a standard deviation of 2 grams.

a. What percentage of the guinea pigs are less than 4 grams below the mean weight?

b. What percentage of the guinea pigs are more than 6 grams above the mean weight?

I have my own graphics calculator too. I can get to a screen where you can enter these values...

Lower:

Upper:

Standard Deviation:

Mean:

I defiantly know we had to use that part of the calculator. If you guys can tell me how to work it out, that would be great!

Thanks in advance!