A Universal Formulation of Uncertainty Relation for Error and Disturbance.

We present a universal formulation of uncertainty relation valid for any conceivable quantum measurement and their observer effects of statistical nature. Owing to its simplicity and operational tangibility, our general relation is also experimentally verifiable. Our relation violates the na{i}ve bound $\hbar/2$ for the position-momentum measurement while respecting Heisenberg's original philosophy of the uncertainty principle. Our error-disturbance relation is found to be a corollary to our relation for errors, the latter of which also entails the standard Kennard-Robertson (Schr{o}dinger) relation as a special case; this attains a unified picture of the three orthodox realms of uncertainty regarding quantum indeterminacy, measurement, and observer effect within a single framework.