Question

find point estimate of population proportion margin error confidence interval number in sample

Answer 1

The confidence interval can be computed with the formula given below considering there are more than 5 successes and/or more than 5 losses:

The point estimate for the population proportion is the sample proportion, and the margin of error is the product of the Z value for the desired confidence level (e.g., Z=1.96 for 95% confidence) and the standard error of the point estimate. Therefore, the standard error of the point estimate is:

This formula is appropriate for samples with at least 5 successes and at least 5 failures in the sample. This was a condition for the Central Limit Theorem for binomial outcomes. If there are fewer than 5 successes or failures then alternative procedures, called exact methods, must be used to estimate the population proportion.