Built by a statistician
Maineblock is run by John Charles, a working statistician in Westbrook, Maine. Its purpose is simple: take hard questions, do the math honestly, and turn the answer into something useful.
That means showing the assumptions instead of hiding them. Testing what can be tested. Calling out what cannot. And never pretending the data says more than it does.
A lot of the work here is about money. The guides, the daily top 7 stock picks, and the valuation tools apply statistical thinking to markets: check the sample, challenge the assumptions, ignore the volume of the claim, and ask what the evidence actually supports. Few fields produce more confidence from less data than investing and trading. That makes good statistical habits especially valuable.
There is a personal reason for that focus. Investing and trading are a passion, built around a conviction that patient, evidence-driven decisions can be one of the most effective ways to build wealth that lasts across generations.
Privacy follows the same philosophy. The calculators run entirely in your browser, so your numbers stay on your device. There are no accounts, no tracking pixels, and no calculator paywalls. And when the data cannot support an answer, the guides say so.
If the decision puts your money, time, or reputation at stake, Maineblock is built for you.
How every tool on this site works
Three steps, applied the same way whether the question is a clinical trial or a stock position. Each one is illustrated with the kind of output the tools actually produce.
State assumptions
Assumption check: live
- n·p = 177.4 ≥ 10, so the normal approximation is OK
- n·(1−p) = 1,596.6 ≥ 10
- Dropout is random (assumed, not verified)
Computed live from your inputs in green, amber, or red. Never a checkbox you tick yourself.
Flag limitations
Drawdown warning
Even at half-Kelly, losing streaks will cut deep. A 50% bankroll drawdown at some point is normal, not a sign the edge vanished.
Every tool states where its math stops working, right next to the result.
Interpret in practical terms
Interpretation
Of 200 stocks that beat earnings estimates, 112 rose the next day. That is 56%, with a margin of error near seven points: the honest range runs from about 49% to 63%, which includes a coin flip.
Every result ships with a practical interpretation. No jargon without an explanation.
Contact
Questions, corrections, or business inquiries: write to [email protected]. Every message is read, and most get a reply within two business days.
The Investor Stats Cheat Sheet
A free three-page PDF: breakeven win rates, stop-loss sizing, volatility drag, reverse valuation, and how to tell a real track record from noise. Plus new tools as they ship.