Got a result that does not match what your textbook, spreadsheet, or software returned? Tell us what you entered and Chris will re-run it.
The most useful message we get is "I entered X and got Y, but I expected Z." Include which calculator you used, the exact values you typed in, and where the number you expected came from: a textbook answer key, a spreadsheet function, R or Python output, or a different online tool. Nine times out of ten the gap traces to something specific, a sample-versus-population divisor, a one-tailed versus two-tailed p-value, or a confidence level typed as 0.95 instead of 95. Once we can see your inputs, we can usually tell you which.
If you think a calculator is using the wrong method entirely, rather than just giving a number you did not expect, name the calculator, the method you believe applies (a specific textbook formula or a named approximation), and, if you have one, a link or citation for it. The editorial standards page lists which formula variant each tool runs; if your report points to a real mismatch between that page and what the calculator does, we correct whichever one is wrong and note the date.
We read every message. Response time is usually one to two business days, and we cannot review a full research write-up or tell you which statistical test to run for your specific study.