In: Statistics and Probability
From a lot containing 25 items, 5 of which are defective, 4 are chosen at random. Let Y be the number of defectives found. Obtain the probability distribution of Y if
(a) the items are chosen with replacement,
(b) the items are chosen without replacement.
a)
here as experiment is done with replacement ; composition of sample remains same therefore events are independent
probability distribution of Y is binomial with parameter n=4 and p=5/25=1/5
b)
as events are not independent; this is hypergeometric distribution:
with parameter N=25 , n=4 and k=5