Question

There are 8 books needing re-shelving in a library where 65% of the library's collection consists of reference books. Let X be the number of reference books a student helper re-shelves out of the 8 on her cart. a) What is the probability that all 8 of them are reference books

Answer 1

Answer:

0.0319

Step-by-step explanation:

To approximate this probability, we shall be using the Bernoulli approximation of the Binomial distribution.

Let p = probability of selecting a reference book = 65% = 0.65

Let q = probability of selecting other books= 1-p = 1-0.65 = 0.35

Now, we want to find the probability that all of these 8 books to be re-shelved are reference book.

We set up the probability as follows;

P(X = 8) = 8C8 •p^8•q^0

P(X = 8) = 1 * (0.65)^8 * (0.35)^0

P(X = 8) = 0.031864481289 which is 0.0319 to 4 decimal places