In: Statistics and Probability
Bowl 1 contains 30 vanilla cookies and 10 chocolate cookies.
What is the likelihood of choosing 15 vanilla and 10 chocolate cookies (without replacement).
Now, instead, what is the likelihood of choosing 15 vanilla and 10 chocolate cookies (without replacement) if you had Bowl 2 which contains 20 of each.
Lets first understand the concept of hypergeometric distribution to solve these two problems.
The hypergeometric distribution is used to calculate probabilities when selections are made from two groups without replacing members of the groups.
Hypergeometric Formula: Suppose a population consists of N items, k of which are successes. And a random sample drawn from that population consists of n items, x of which are successes. Then the hypergeometric probability is:
where
Bowl 1:
Bowl 1 contains 30 vanilla cookies and 10 chocolate cookies, then the likelihood of choosing 15 vanilla and 10 chocolate cookies without replacement is computed using hypergeometric formula.
In this context,
Then, the likelihood of choosing 15 vanilla and 10 chocolate cookies without replacement= P(X=15)
Answer: The likelihood of choosing 15 vanilla and 10 chocolate cookies without replacement is 0.003856
Bowl 2:
Bowl 1 contains 20 vanilla cookies and 20 chocolate cookies, then the likelihood of choosing 15 vanilla and 10 chocolate cookies without replacement is computed similarly we did above,
In this case,
Then, the likelihood of choosing 15 vanilla and 10 chocolate cookies without replacement= P(X=15)
Answer: The likelihood of choosing 15 vanilla and 10 chocolate cookies without replacement is 0.07121