Reliability

The word reliability has at least four different meanings. The first of these is in an engineering context, where reliability refers to the likelihood that a piece of equipment will not break down within some specified period of time. The second meaning is synonymous with dependability, as in "She is a very reliable employee" (i.e. she is a good worker). The third has to do with the sampling variability of a statistic. A percentage, for example, is said to be reliable if it does not vary by any nonnegligible amount from one sample to another of the same size and that are drawn in the same manner from the same population.

The fourth meaning is the one focused upon in this entry. A measuring instrument is ...