Cronbach's Alpha Explained: Formula, Worked Example, Python/R Code, and a Free Calculator
You built a survey with several questions that are supposed to measure the same thing (say, "job satisfaction" or "stats anxiety"). Before you avera…
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Four checks I run on any number someone quotes at me
Four checks I run on any number someone quotes at me Someone hands you a number with a sentence attached. A brand report. A study abstract. A headli…
Why 7,167 of 11,000 sampled projects get no score, gate by gate
Every ranking is also a list of what it declined to rank. In Porchlamp's snapshot of 14 October 2026, 11,000 projects were sampled and 3,833 earned…
Backtest a betting idea before you trust it
Originally published at quantplus.win . Sports betting backtesting software runs a betting rule over past games using only the prices and informatio…
DemoDoctor: Bad Robot Demonstrations Are Detectable. Do They Matter?
Inject known faults into robot demonstrations, detect them without labels, and measure what they cost a policy. The honest answer so far: I could no…
Six ways an auto clicker gives itself away, using nothing but timestamps
I run a small click speed test, CPSBench . Once a site has a leaderboard, the first entries that look too good arrive almost before the real ones do…
Measuring How Cost Scales by Counting Instead of Timing
Code: Megapixel99/countfn Every empirical complexity tool I could find on either registry measures elapsed time. PyPI's big-O estimates the class fr…
A Curve Fitter That Refuses to Answer
Code: Megapixel99/undetermined Plenty of libraries fit a curve to measurements and hand you back a number. undetermined hands back a number with the…
Forecasting the NFL GOAT QB with Artificial Intelligence: The 2026 Update
Last year I wrote an article that used an AI system to research and predict the probability of Patrick Mahomes surpassing Tom Brady as the greatest…
My Comment Section Designed My Next Experiment. Then It Made Me Freeze My Predictions.
Ten days ago I published an article about a failure mode: tell a language model "a scanner flagged this code" and some models agree with everything.…
Who gets rated higher: age, age gap and the reciprocity myth - from 24 million ratings
In the previous piece I went through 24 million ratings from our app Rate Me (people rate each other's photos 1-10) and showed four things: the dip…
NBA play-in odds are not playoff odds: simulating the play-in tournament instead of guessing it
In baseball, American football and hockey, "make the playoffs" is one line: finish above it and you're in. When I built an NBA version of my playoff…
NHL playoff odds for 2026-27: 84 games, the wild card rule, and why I don't trust my own model in September
I build Monte Carlo simulators that turn standings and schedules into playoff probabilities. After baseball, American football and soccer, I assumed…
Correct score, BTTS and Over/Under probabilities with Dixon-Coles: what I learned building it for MLS and Liga MX
Most football prediction pages give you three numbers — home, draw, away — and no way to check where they came from. I wanted the opposite: one mode…
Percentiles, the IQR and the 1.5 Outlier Rule: How to Flag a Bad Row
By Michael Nocito , data analyst · Published August 9, 2026 By the end of this page you can compute quartiles by hand, build the standard outlier fe…
What Is a P-Value? Worked by Shuffling Nine Real Orders 126 Ways
By Michael Nocito , data analyst · Published August 9, 2026 By the end of this page you can say what a p-value measures in one sentence, compute one…
Moving Averages: Smoothing a Series Without Smoothing Away the Truth
By Michael Nocito , data analyst · Published August 9, 2026 By the end of this page you can build a moving average by hand, choose a window length o…
Choice Leaks: I Tried to Generate 100 Random Digits and Failed in Four Measurable Ways
This morning a friend handed me a test for consciousness over Telegram. It was three sentences long and it had my name on it. If a thing has conscio…
How accurately can complex option trades be signed? First grading against exchange truth
To build a dealer book from the options tape you must decide, print by print, who bought. For simple orders the quote rule does that. But on the day…
Correlation Is Pairwise. Multicollinearity Isn't.
Almost every regression project I've seen in the last decade starts the same way. Load the data, df.corr() , plot the heatmap, scan for red squares,…
Running Multiple A/B Tests at Once: When Overlap Is Safe
Every experimentation program hits this question within its first few months: test A is running on the homepage, the checkout team wants to launch t…
Checking your A/B test every morning makes it lie to you
You launch the test on Monday. You check the dashboard each morning, because of course you do. On Thursday it reads p = 0.04, you call it, and you s…
Multi-Armed Bandit Testing: How It Works and When to Use
A multi-armed bandit is an algorithm that decides how to split traffic across several variations while a test is still running, shifting more visito…
How to Choose a Minimum Detectable Effect (MDE)
You have opened your sample-size calculator, entered your baseline conversion rate, kept the defaults for significance and power, and now the calcul…
You Don't Need a Math PhD for Data Science — You Need to Stop Skipping the Boring Step
Ask someone switching into data science what worries them and it's almost always the same thing: do I know enough math? So they spend weeks on gradi…
I read the metric libraries of five widely-used eval tools. The metric was never the hard part.
Every LLM eval tool sells you the same headline: a big bag of ready-made metrics. Fifty of them. Seventy. Pick one, call evaluate(), get a number. T…
Your eval monitor fired on four days this week. At your sample size, that was the most likely count
A team I compared notes with recently runs continuous evals on production traffic: an LLM judge scores a sample of traces, the scores land on a dash…
Part 6 - STATISTICS
Bernoulli, Binomial Distribution & Central Limit Theorem Explained from First Principles When I first started learning probability, I came acros…
Your A/B test has three goals and they disagree. Now what?
Every A/B testing tutorial ends the same way: run the test, wait for significance, ship the winner. Then you run a real test and variant B converts…
Part 5 - STATISTICS
Non-Gaussian Distributions Explained from First Principles (Beginner Friendly) As we all know, the real-world dataset is not normalized , but most o…