Problem 151E

Consider the visits that result in leave without being seen (LWBS) at an emergency department in Example 2-8. Assume that four visits that result in LWBS are to be randomly selected (without replacement) for a follow-up interview.

(a) What is the probability that all selected visits are from hospital 4?

(b) What is the probability that no selected visits are from hospital 4?

(c) What is the probability that all selected visits are from the same hospital?

Solution

Step 1 of 3

Given that no.of visits in LWBS=N=953

In Hospital 4 no.of visits=k=242

No.of randomly selected visits=n=4

Let X be the no.of visits in hospital 4

Here X is following hypergeometric distribution

The pmf of hypergeometric distribution is

a) We have to find the probability of all selected visits from hospital 4

Now we have to find

=0.0041

Hence the probability of all selected visits from hospital 4 is 0.0041