Instrumentation concepts interval

Instrument hardware should be validated prior to routine use, after repair, and at regular time intervals. Computer systems should be validated during, and at the end of, the development process and after software updates. Computer systems with complex software are frequently gradually developed over many years. It is critical to note that quality cannot be tested into a product or system at the final testing stages. To ensure quality during the development process, the life cycle concept has been developed. 

The concept of a confidence interval around the least squares calibration line will again become important in the calculation of an instrument s detection limit for a given analyte. In other words, how reliable is this detection limit ... 

The manufacture of primitive stone tools and fire required a qualitative appreciation for the most common measures of mass, time, number, and length. The concept of time has been appreciated for millennia. In comparative terms it is qualified by longer and shorter, sooner and later, more or less. Quantitatively, it has been measured in seconds, hours, days, lunar months, and years. Calendars have existed for well over 6000 yr and clocks—instruments to measure time intervals of less than a day—were common as long as 6000 yr ago. Chronometers are devices that have higher accuracy and laboratory models have a precision of 0.01 s. 

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