A researcher wishes to estimate, with 95% confidence, the population proportion of adults who think Congress is doing a good or excellent job. Her estimate must be accurate within 1% of the true 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 26% of the respondents said they think Congress is doing a good or excellent job. (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.) (b) What is the minimum sample size needed using a prior study that found that 26% of the respondents said they think Congress is doing a good or excellent job? n= (c) How do the results from (a) and (b) compare? A. Having an estimate of the population proportion reduces the minimum sample size needed. B. Having an estimate of the population proportion raises the minimum sample size needed. C. Having an estimate of the population proportion has no effect on the minimum sample size needed.

Holt Mcdougal Larson Pre-algebra: Student Edition 2012

1st Edition

ISBN:9780547587776

Author:HOLT MCDOUGAL

Publisher:HOLT MCDOUGAL

Chapter11: Data Analysis And Probability

Section11.4: Collecting Data

Problem 6E

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Question

A researcher wishes to estimate, with 95% confidence, the population proportion of adults who think Congress is doing a good or excellent job. Her estimate must be accurate within 1% of the true 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 26% of the respondents said they think Congress is doing a good or excellent job.

_________________________________________________________

(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.)

(b) What is the minimum sample size needed using a prior study that found that 26% of the respondents said they think Congress is doing a good or excellent job?

n= ____

A. Having an estimate of the population proportion reduces the minimum sample size needed.

B. Having an estimate of the population proportion raises the minimum sample size needed.

C. Having an estimate of the population proportion has no effect on the minimum sample size needed.

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