A random sample of 600 registered voters in the Phoenix is asked if they favor the employ of oxygenated fuels year-round to reduce air pollution. If more than 480.0 voters respond positively, we will conclude that the more than 60% of the voters favor the employ of these fuels.

(a) Determine the probability of type I error if exactly 60% of the voters favor the use of these fuels.

(b) Determine the type II error probability if 75% of the voters favor this action?

Hint: use the normal approximation to the binomial.