Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 2

FBI Report: Larceny Thirty small communities in Connecticut (population near 10,000 each) gave an average of
= 138.5 reported cases of larceny per year. Assume that is known to be 42.6 cases per year (Reference: Crime in the United States, Federal Bureau of Investigation).
(a) Find a 90% confidence interval for the population mean annual number of reported larceny cases in such communities. What is the margin of error
(b) Find a 95% confidence interval for the population mean annual number of reported larceny cases in such communities. What is the margin of error
(c) Find a 99% confidence interval for the population mean annual number of reported larceny case in such communities. What is the margin of error
(d) Compare the margins of error for parts (a) through (c). As the confidence levels increase, do the margins of error increase
(e) Critical Thinking Compare the lengths of the confidence intervals for parts (a) through (c). As the confidence levels increase, do the confidence intervals increase in length