Determine whether each of the following statements is a statement of fact or a statement of opinion, and explain why:

a. “I am sure that the driver was drunk because he pulled up next to me at the stoplight, then threw the car into reverse and backed a quarter of a mile down the one-way street.”

b. “The driver who was arrested for drunk driving ran a stop sign, then made a U-turn so that he could enter the highway. When he was arrested for erratic driving, his Breathalyzer reading was 0.19.”