Answer
a)Without replacement.
b) The probabilities given the two way are really close to each other, and when they choose a random person from the population, it is really unlikely to choose a person chosen before.
Work Step by Step
a) It is better to take samples without replacement, because even this way it takes a long time to inspect but with replacement, it would take even longer.
b)Because when performing statistical methods, the probabilities given the two way are really close to each other, and when they choose a random person from the population, it is really unlikely to choose a person chosen before, therefore it is considered as doing it with replacement.
