# Confidence Intervals: Confidence Level, Sample Size, and Margin of Error

Confidence Intervals: Confidence Level, Sample Size, and Margin of Error

All confidence intervals studied in an introductory statistics course have in common the underlying relationships between the confidence level, sample size, and margin of error. Namely, for a fixed sample size the margin of error varies with the confidence level, and for a fixed confidence level the margin of error varies inversely with a sample size. Furthermore, the sample statistic being used to estimate a population parameter is always located at the midpoint of the confidence interval.