# Proportions - Standard error and confidence interval

Ms. Maria Wilson is considering running for mayor of the town of Bear Gulch, Montana. Before completing the petitions, she decides to conduct a survey of voters in Bear Gulch. A sample of 400 voters reveals that 300 would support her in the November election.

Estimate the value of the population proportion.

Compute the standard error of the proportion.

Develop a 99 percent confidence interval for the population proportion

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#### Solution Preview

99% Confidence limits for proportions=

Estimate the value of the population proportion.

p= 75.00% =300/400

Compute the standard error of the proportion.

q=1-p= 25.00%

n=sample size= 400

standard ...

#### Solution Summary

The solution estimates the value of the population proportion, computes the standard error of the proportion and develops a 99 percent confidence interval for the population proportion.