Question

Two percent of mobile phones produced at a factory are defective. Which of the following is a binomial experiment?
Selecting phones randomly until a non-defective phone is chosen
Selecting phones randomly until 200 defective phones are chosen
Selecting 200 phones randomly and recording whether each phone is defective
Selecting a group of phones randomly and recording the number of defective phones in the group

Answer 1

I know the last one is wrong so x that out

Answer 2

I believe it is 1 or 2 or A or B please help me

Answer 3

it is 1

Answer 4

thanks so much

Answer 5

it was wrong