Refers to any duration of observations of the considered items - either in actual operation or in storage, readiness, etc., but excludes downtime due to a failure. Note: In definitions where "time" is used, this parameter may be replaced by distance, cycles, or other measures of life as may be appropriate. This refers to terms such as acceleration factor, wear-out failure, failure, rate, mean life, mean-time-between-failures, mean-time-to-failure reliability, and useful life.

That part of active corrective maintenance time during which function check out is performed. [4: 191-08-13]

That element of maintenance time during which the item is enclosed and extraneous material not required for operation is removed. [7]

That element of downtime during which no maintenance is being accomplished on the item because of either supply delay or administrative reasons. [7]

The time interval during which an item is in a down state. [4: 191-09-08]

That part of active corrective maintenance time during which fault correction is performed. [4: 191-08-11]

That part of active corrective maintenance time during which fault localization is performed. [4:191-08-15]

That time during which an item is in reserve (in the inactive inventory). [7]

That element of maintenance time during which the needed item or items are being obtained from designated organization stock rooms. [7]

That element of uptime during which the item is performing its designated mission. [7]

The time necessary to introduce any specific change(s) to an item to improve its characteriustics or to add new ones. [7]

That element of maintenance time needed to obtain the necessary test equipment and maintenance manuals, and set up the necessary equipment to initiate fault location. [7]

A time-series is a set of ordered observations on a quantitative characteristic of an individual or collective phenomenon taken at different points of time.

Difference between the upper and the lower tolerance limits. [2: 1.4.4]

Specified values of the characteristic giving upper and/or lower bounds of the permissible value. Notes: (1) This term should not be confused with natural process limits or tolerance interval. (2) Tolerance limits may be set on the basis of natural process limits. [2: 1.4.3]

A test in which the statistic used is one-dimensional and in which the critical region is the set of values less than a first critical value and the set of values greater than a second critical value. Note: The choice between a one-sided test and a two-sided test is determined by the alternative hypothesis. [1: 2.74]

The probability of committing the error of the first kind. Notes:
(1) It is always less than or equal to the significance level of the test.
(2) Sometimes called a "type 1 risk". [1: 2.76]

The probability of committing an error of the second kind. Notes:
(1) Its value, usually designated , depends on the real situation and can only be calculated if the alternative hypothesis is adequately specified.
(2) Sometimes called a "type II risk".[ 1: 2.78]