Note that in adversarial (or potentially adversarial) situations, error is not independent and identically distributed. If your acceptance spec for gold coins is “25g +/- 0.5g”, you should expect your suppliers to mostly give you coins near 24.5g. Network errors are also correlated, either because they ARE an attack, or because some specific component or configuration is causing it.
Note that in adversarial (or potentially adversarial) situations, error is not independent and identically distributed. If your acceptance spec for gold coins is “25g +/- 0.5g”, you should expect your suppliers to mostly give you coins near 24.5g. Network errors are also correlated, either because they ARE an attack, or because some specific component or configuration is causing it.