# Math Help - Margin error of a confidence interval

1. ## Margin error of a confidence interval

Is it true that if you increase the confidence interval then the margin of error of a confidence interval would also increase since larger confidence equals larger interval?
Is it also true that quadrupling the sample size would make the margin of error of a confidence interval smaller?

2. ## Re: Margin error of a confidence interval

An increase in the interval means more uncertainty in the estimate as a general feature, so yes larger interval means larger margin of error probabilistically in general.

In a typical application, quadrupling would half the interval if you were going to use something like a t-statistic or a asymptotic Normal statistic.