Numerical-Methods on The Standard Errorhttps://jongha-jeon-dev.github.io/standarderror/tags/numerical-methods/Recent content in Numerical-Methods on The Standard ErrorHugo -- 0.123.7en-gbThu, 27 Aug 2026 00:00:00 +0000Linear Algebra 1: The Condition Number Is the Error Bar on Your Solvehttps://jongha-jeon-dev.github.io/standarderror/lectures/linear-algebra-1-condition-number/Thu, 27 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/lectures/linear-algebra-1-condition-number/A 14 by 14 system whose answer is all ones, solved to a residual at machine precision, returning entries between -4.9 and +8.5 — and the one number on the matrix that predicts it.Linear Algebra 2: Least Squares Three Ways, and Only Two Survivehttps://jongha-jeon-dev.github.io/standarderror/lectures/linear-algebra-2-least-squares-three-ways/Thu, 27 Aug 2026 00:00:00 +0000https://jongha-jeon-dev.github.io/standarderror/lectures/linear-algebra-2-least-squares-three-ways/The closed form in every regression textbook is a correct formula and a bad algorithm. On exact data it returns coefficients wrong by 14 percent where two other routes get ten decimal places.