A researcher wishes to estimate, with

90%

confidence, the population proportion of likely U.S. voters who think Congress is doing a good or excellent job. Her estimate must be accurate within

44%

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

44%

of the respondents said they think Congress is doing a good or excellent job.

(c) Compare the results from parts (a) and (b).

Question content area bottom

Part 1

(a) What is the minimum sample size needed assuming that no prior information is available?

nequals=enter your response here

(Round up to the nearest whole number as needed.)

Part 2

(b) What is the minimum sample size needed using a prior study that found that

4444%

of the respondents said they think Congress is doing a good or excellent job?

nequals=enter your response here

(Round up to the nearest whole number as needed.)

Part 3

(c) How do the results from (a) and (b) compare?

A.

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

B.

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

C.

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