Question

In a randomly selected sample of 400 registered voters in a community, 160 individuals say that they plan to vote for Candidate Y in the upcoming election.

(a) Find the sample proportion planning to vote for Candidate Y. (Round your answer to two decimal places.)

(b) Calculate the standard error of the sample proportion. (Round your answer to three decimal places.)

(c) Find a 95% confidence interval for the proportion of the registered voter population who plan to vote for Candidate Y. (Round your answers to three decimal places.)

(d) Find a 98% confidence interval for the proportion of the registered voter population who plan to vote for Candidate Y. (Round your answers to three decimal places.)

Answer 1

sample proportion =  

Standard Error =

n = 400



Lower Limit =
upper Limit =
95% Confidence interval is ( 0.352 , 0.448 )
( 0.352 < P < 0.448 )

Lower Limit =
upper Limit =
98% Confidence interval is ( 0.343 , 0.457 )
( 0.343 < P < 0.457 )