The librarian at the New York City Public Library has asked her assistant for an interval estimate of the mean number of books checked out each day.The assistant took a sample and found the mean to be 880 books.She provides the librarian with an interval estimate of between 790 and 970 books checked out per day.An efficient,unbiased point estimate of the number of books checked out each day at the New York City Public Library is:
A)790
B)880
C)90
D)None of these choices.

Question

Quizplus · Accepted Answer

The assistant already provided the interval estimate of between 790 and 970 books checked out per day, which means that any point estimate within this range could be considered efficient and unbiased. However, the sample mean that the assistant obtained was 880 books, which falls right in the middle of the interval estimate. Therefore, the best choice for an efficient, unbiased point estimate in this case would be the sample mean of 880 books. Thus, the answer is B.

The Librarian at the New York City Public Library Has