Rachel loves to bake cookies, but she has an old oven that has trouble maintaining a constant temperature.

Rachel loves to bake cookies, but she has an old oven that has trouble maintaining a constant temperature. If the acceptable temperature range for making the cookies is 350 plus or minus 25 degrees, what is the allowable standard deviation in the temperature of her oven in order to achieve a Six Sigma level of quality? (Round your answer to 3 decimal places.)