The purpose of this standard is to establish the procedure to be followed to estimate, with pre-established error limits, the average of a characteristic of a population. It is shown here how to determine the volume n of the sample, to be extracted from the population under examination, so that its mean x is included, in 100 — cases out of 100, within the interval the population average. A similar determination can be made for the case in which the interval is expressed as a percentage of the average; in this case the interval is indicated with X ± D, where D is the percentage deviation 100 -4— ■ and in dimensional measurements.
UNSIDER 28-1959 history
1959UNSIDER 28-1959 Quality inspection. The number of observations necessary for estimating the mean with predetermined error limits