>Look at the histogram and think about what distribution one could reasonably impute from samples. And what you would set as bounds for "outliers", per your needs. While we're at it, let me also say that it might be useful to specify outlier bounds not just based on the spread in sample values, but the costs/payoffs they imply for your application.

Only people with prior education/training in statistics are capable of doing this. The people who don't need a textbook.

Something like 60% of US adults read at or below the 6th grade level, and 25% of US adults struggle to comprehend graphs or charts entirely. Someone who has no idea what a standard deviation is can't intuit about distributions. I think you're dramatically overestimating the average person.