A pit boss suspects that a roulette wheel is out of balance. A roulette wheel has 18 black slots, 18 red slots, and 2 green slots. The pit boss spins the wheel 500 times and records the following frequencies:
Outcome _________________ Frequency
Black ................................. 233
Red ................................... 237
Green ................................. 30
Is the wheel out of balance? Use the a = 0.05 level of significance.