Science and engineering in Manchester chemist visited Manchester in the 1840s. In his research in Manchester, Smith discovered the existence of acid rain, a by product of the industrial revolution. Smith consequently pushed for greater environmental awareness and helped to found the Noxious Vapours Abatement Society in Manchester, which raised awareness of the consequences of poor air. Joseph Whitworth was an engineer and inventor who hailed from Stockport, Cheshire (now Greater Manchester). A talented mechanic amongst various other engineering roles, for long periods of his life, he worked in factories in Manchester. Whitworth would ultimately devise a standard screw thread system, the first of its
Accuracy and precision use the terms "bias" and "variability" instead of accuracy and precision: bias is the amount of inaccuracy and variability is the amount of imprecision. A measurement system can be accurate but not precise, precise but not accurate, neither, or both. For example, if an experiment contains a systematic error, then increasing the sample size generally increases precision but does not improve accuracy. The result would be a consistent yet inaccurate string of results from the flawed experiment. Eliminating the systematic error improves accuracy but does not change precision. A measurement system is considered "valid" if it is both "accurate" and