Dackohn
Developer & maintainer, Stat-Tools
Stat-Tools is built and maintained by an independent developer who works under the name Dackohn. It started from a simple frustration: most free statistics calculators either give you a bare number with no explanation, or quietly use rough in-browser approximations you can't verify. The goal here is the opposite — correct numbers you can trust, with a plain-English explanation of what they mean.
How the tools are built
The inferential calculators (t-tests, ANOVA, regression, confidence intervals, and so on) run on a Python 3 backend using SciPy and NumPy — the same peer-reviewed scientific-computing libraries used in academic and industry research — rather than hand-coded approximations. Probability and combinatorics tools use exact closed-form math in the browser. Every tool is cross-checked against SciPy's reference output (and therefore against R, SPSS, and Stata, which share those algorithms) before it ships. The full approach is documented, openly, on the methodology & accuracy page.
How the guides are written
The guides are written to be accurate first and readable second. Definitions, formulas, and rules of thumb are checked against standard references — including the NIST/SEMATECH e-Handbook of Statistical Methods and OpenStax Introductory Statistics — and they deliberately call out common misconceptions rather than repeating them. Each guide shows when it was last reviewed.
Corrections & contact
Accuracy matters more than ego here. If you spot an error — in a calculation, a formula, or an explanation — please email [email protected]. Every report is treated as a bug and investigated, and genuine fixes are credited.