Kiera wanted to find the approximate number of historical books at the library she works at. She used the computer to randomly take a sample of 80 books and found that 6 of them were considered historical books. There are 21,360 books at this library. What is the best estimate of the amount of historical books at this library?

A sample of 80 books was taken randomly using a computer and 6 of them were considered to be historical books. It means probability of sample would be 6 out of 80 i.e. P = 6 over 80 = 0.075 or 7.5%. It says there are 21,360 books in the library, so Population would be 21,360 books. We can use outputs of the sample survey to represent complete collection of books in the library. So best estimate of total historical books in the library would be 7.5% of total population. Best estimate = 7.5% of 21,360 Best estimate = 0.075 x 21,360 Best estimate = 1602 books. Hence, there are approximately 1602 historical books in the entire library.