Posts on The Standard Errorhttps://jongha-jeon-dev.github.io/standarderror/posts/Recent content in Posts on The Standard ErrorHugo -- 0.123.7en-gbWed, 19 Aug 2026 00:00:00 +0000Two Thirds of the Move Happens Before the Headlinehttps://jongha-jeon-dev.github.io/standarderror/posts/two-thirds-of-the-move-before-the-headline/Wed, 19 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/two-thirds-of-the-move-before-the-headline/A paper measured 'buy the rumour, sell the news' on 4.57 million articles, and the sayings mostly holdThe Chip Cycle Is Forecastable. The Shortage Is a Different Question.https://jongha-jeon-dev.github.io/standarderror/posts/the-chip-cycle-is-forecastable/Tue, 18 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/the-chip-cycle-is-forecastable/A delayed feedback loop, an echo state network, and a result I had the wrong way roundThe Jeonse Number That Is Not on the Contracthttps://jongha-jeon-dev.github.io/standarderror/posts/the-jeonse-number-not-on-the-contract/Fri, 14 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/the-jeonse-number-not-on-the-contract/A deposit's safety margin is two published ratios divided — and the interesting part is what that arithmetic cannot tell youYour Index Fund Owns 503 Companies and Is About Three Betshttps://jongha-jeon-dev.github.io/standarderror/posts/your-index-fund-owns-503-companies-and-is-three-bets/Fri, 14 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/your-index-fund-owns-503-companies-and-is-three-bets/Concentration has a formula, and running it is unkind to both sides of the argumentIndividuals Sold a Record Amount on the Best Day in Market Historyhttps://jongha-jeon-dev.github.io/standarderror/posts/individuals-sold-a-record-amount-on-the-best-day/Thu, 13 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/individuals-sold-a-record-amount-on-the-best-day/The gap between what an index returns and what its investors earn is arithmetic — and I was wrong about where it comes fromI Trained 2,000 Models on a Coin Flip and the Best One Looked Greathttps://jongha-jeon-dev.github.io/standarderror/posts/i-trained-2000-models-on-a-coin-flip/Fri, 07 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/i-trained-2000-models-on-a-coin-flip/A 55.3% hit rate, a p-value of 0.0008, and not one shred of signal in the dataThe KOSPI's Record Day Was Not a Fat-Tail Problemhttps://jongha-jeon-dev.github.io/standarderror/posts/the-kospi-record-day-was-not-a-fat-tail-problem/Fri, 07 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/the-kospi-record-day-was-not-a-fat-tail-problem/A +17.91% session, a 12-sigma move, and the assumption that actually brokeWhy Every Bus You Catch Is on a Longer-Than-Average Gaphttps://jongha-jeon-dev.github.io/standarderror/posts/why-every-bus-is-on-a-longer-than-average-gap/Fri, 07 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/why-every-bus-is-on-a-longer-than-average-gap/Your class was bigger than average, your queue was slower, and your bus was late. One formula, and no bias in sightYour 90% Prediction Interval Covers 42% of the Timehttps://jongha-jeon-dev.github.io/standarderror/posts/your-90-percent-interval-covers-42-percent/Fri, 07 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/your-90-percent-interval-covers-42-percent/Conformal prediction's guarantee is real, and it does not say what people repeat about itWhy My Integrator Exploded at t = 355, Every Single Timehttps://jongha-jeon-dev.github.io/standarderror/posts/why-my-integrator-exploded-at-355/Thu, 06 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/why-my-integrator-exploded-at-355/Two silent numerical bugs, and the kind of test that actually catches themYour Forecast Is Probably Just Repeating Yesterdayhttps://jongha-jeon-dev.github.io/standarderror/posts/your-forecast-is-probably-just-repeating-yesterday/Thu, 06 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/posts/your-forecast-is-probably-just-repeating-yesterday/A model scores 99% on a series of coin flips. Here is why, and the one number that would have caught it