Exam 9: Introduction to Estimation

Physicians A random sample of 200 physicians shows that there are 36 of them who make at least $400,000 a year. {Physicians Narrative} Construct a 99% confidence interval estimate of the population proportion of physicians who make at least $400,000 a year, and explain how to use it to test the hypotheses.

Because n is an integer and we want the bound on the error of estimation to be no more than a given amount, any non-integer value found for n must always be rounded ____________________.

If the population standard deviation is guesstimated, and it turned out to be larger than you assumed, then the sample size you calculated is ____________________ than it needs to be.

An unbiased estimator is a sample statistic whose expected value equals the population parameter.

An interval estimator estimates the value of an unknown ____________________.

To produce a confidence interval estimator for the total, we multiply the lower and upper confidence limits of the interval estimator of p by ____________________.

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:

An unbiased estimator is ____________________ if its variance gets smaller as n gets larger.