I conduct pre/post analyses looking at a health metrics (such as BMI) for a sample population. The sample might be around 75 people for a total population of about 500. One of the questions I get all the time is how much does this change represent the overall population (who have not been part of the analysis).
I have been thinking about ways to do this, looking at MOE of the sample and if the error bars overlap between pre and post, then there is no statistically detectable difference at the aggregate population level. Is this the best way to do this?