From the following list of hypothetical situations, identify those that are independent events using the given probabilities of each event and the formal definition of independence.
In a yearly weather survey of a city, 32% of the days had precipitation, 25% of the days were weekend days, and 8% of the days had precipitation and were weekend days.
In a human trait study, 48% of the individuals had brown eyes, 44% of the individuals had brown hair, and 25% of the individuals had brown eyes and brown hair.
In a yearly highway study, 40% of the drivers were speeding, 10% of the drivers got into an accident, and 5% of the drivers were speeding and got into an accident.
In a college course survey, 20% of students received an A in chemistry, 25% of students received an A in biology, and 5% of students received an A in both chemistry and biology.