A telephone poll of 1000 adult Americans was reported in a magazine. One of the questions asked was "What is the main problem facing the country?" Suppose 22% answered "crime". We are interested in the population proportion of adult Americans who feel that crime is the main problem.

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A telephone poll of 1000 adult Americans was reported in a magazine. One of the questions asked was "What is the main problem facing the country?" Suppose 22% answered "crime". We are interested in the population proportion of adult Americans who feel that crime is the main problem.

NOTE: If you are using a Student's t-distribution, you may assume that the underlying population is normally distributed. (In general, you must first prove that assumption, though.)

Please label each part

Part (c)
Construct a 95% confidence interval for the population proportion of adult Americans who feel that crime is the main problem.
(i) State the confidence interval. (Round your answers to four decimal places.)
(ii) Sketch the graph.
a
C.L. =
-
P'
(iii) Calculate the error bound. (Round your answer to four decimal places.)
O Part (d)
Suppose we want to lower the sampling error. What is one way to accomplish that?
O increase the level of confidence
decrease the level of confidence
decrease the standard deviation
decrease the sample size
O Part (e)
The sampling error given by the company which conducted the poll is ±3%. Explain what the +3% represents.
O This means the interval created around the point estimate of 22% is 19%-25%. The stated population proportion is within 3 percentage points of the true population
proportion.
It means that the stated population proportion may be off by 3 percentage points due to errors in the survey.
This means that the company is between 92% and 98% confident that the population proportion falls within the confidence interval.
This means that there is a 3% chance that the stated population proportion is not correct.
Transcribed Image Text:Part (c) Construct a 95% confidence interval for the population proportion of adult Americans who feel that crime is the main problem. (i) State the confidence interval. (Round your answers to four decimal places.) (ii) Sketch the graph. a C.L. = - P' (iii) Calculate the error bound. (Round your answer to four decimal places.) O Part (d) Suppose we want to lower the sampling error. What is one way to accomplish that? O increase the level of confidence decrease the level of confidence decrease the standard deviation decrease the sample size O Part (e) The sampling error given by the company which conducted the poll is ±3%. Explain what the +3% represents. O This means the interval created around the point estimate of 22% is 19%-25%. The stated population proportion is within 3 percentage points of the true population proportion. It means that the stated population proportion may be off by 3 percentage points due to errors in the survey. This means that the company is between 92% and 98% confident that the population proportion falls within the confidence interval. This means that there is a 3% chance that the stated population proportion is not correct.
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