Question

9. Suppose the probability that a page of a book report is properly prepared is 0.25. What is the probability that there will be exactly one page with at least one error in a report of 5 pages

Answer 1

Probability that a page of book reports is properly prepared, is 0.25.

So, the probability that there would be at least 1 error in a page of book reports, is 1-0.25, ie. 0.75.

We have to find the probability that there would be eaxactly one page, with at least 1 error, in a 5 page report.

Now, if X be the random variable denoting the number of pages out of these 5, which have at least 1 error, then

X follows binomial with n = 5 and p = 0.75

So, the PMF of X is given as

We have to find

So, the chance that there are exactly 1 pages in a report of 5 pages, with at least 1 error is 0.0146