Assume that you toss a fair six-faced die two times.
1. What is the probability that you get an even number at the first toss? (Show work and write the answer in simplest fraction form)
2. What is the probability that the sum of the two tosses is at least 7, given that you get an even number in the first toss? (Show work and write the answer in simplest fraction form)
3. If event A is "Getting an even number in the first toss" and event B is "The sum of two tosses is at least 7". Are event A and event B independent? Use mathematical expression to justify your answer.