In the previous post, we saw how the margin of error at a specified confidence interval is estimated. The margin of error, and thereby the confidence in the data, varies with the number of samples and the confidence interval.
Here are five calculations with varying numbers of samples (500, 1041 and 2000) for three confidence intervals (90%, 95%, 99%).
As the sample size increases, the margin of error decreases, i.e., the more people you survey, the more confident you can be that your results are closer to the “true” population value (provided the sample is representative). However, the reduction diminishes as the sample size goes beyond 1000.
