1) In a survey of 3497 ?adults, 1485 say they have started paying bills online in the last year. Construct a? 99% confidence interval for the population proportion. Interpret the results.
A? 99% confidence interval for the population proportion is (___, ____) ?(Round to three decimal places as? needed.)
2) Construct the confidence interval for the population mean μ.
C = 0.95?, x = 15.6?, σ = 2.0?, and n = 55
A 95?% confidence interval for μ is (____, _____) is (Round to one decimal place as? needed.)
3) A researcher wishes to? estimate, with 95?% ?confidence, the population proportion of adults who are confident with their? country's banking system. His estimate must be accurate within 3?% of the population proportion.
?(a) No preliminary estimate is available. Find the minimum sample size needed.
?(b) Find the minimum sample size? needed, using a prior study that found that 32?% of the respondents said they are confident with their? country's banking system.
?(c) Compare the results from parts ?(a) and ?(b).
(a) What is the minimum sample size needed assuming that no prior information is? available?
n = ___ ?(Round up to the nearest whole number as? needed.)