3. In which of the following situations is it reasonable to use the Binomial
distribution for the random variable X
1. A multiple-choice exam contains 20 questions with 5
possible answers. An A. P. Statistics student who repeatedly
missed class could only guess an answer to each question
Let X denote the number of questions answered until a
correct answer is chosen.
II. Doctors estimate that the probability of a pregnant women
having identical twins is approximately 0.004. Of the 1355
pregnant women who are maternity patients at a city
hospital over a one-year period, X denotes the number of
women having identical twins.
III. The manufacturers of cell phones have collected failure data
from random samples of size 100 from five different models
of cell phones. The total number of cell phone failures is
recorded
(A) I only
(B) II only
(C) I and II only
(D) II and III only
(E) I, II and III