In Bengal, 30% of the population has a certain blood type.What is the probability that exactly four out of a randomly selected group of 10 Bengalis will have that blood type?
1 Answer
Explanation:
The probability that four out of the ten people have that blood type is
The probability that the other six do not have that blood type is
We multiply these probabilities together, but since these outcomes can happen in any combination (for example, person 1, 2, 3, and 4 have the blood type, or perhaps 1, 2, 3, 5, etc.), we multiply by
Thus, the probability is
———
This is another way to do it:
Since having this specific blood type is a Bernoulli trial (there are only two outcomes, a success and a failure; the probability of success,
We will use
When using this function on your calculator, enter
#"binompdf"(10, 0.3, 4) ~~ 0.200#