An SRS of 20 recent birth records at the local hospital were selected. In the sample, the average birth weight was 3.44 kg and the standard deviation was 0.21kg. Assume that in the population of all babies born in this hospital, the birth weights follow a Normal distribution, with some mean μ.

We are interested in a 95% confidence interval for the population mean birth weight. The margin of error associated with the confidence interval is: