Sampling Plans - Quick Tab

Select the Quick tab of the Sampling Plans dialog box to access the options described here.

Distribution

The Distribution box contains three options: Normal means, Binomial proportions, and Poisson frequencies. Use this box to specify the type of quality characteristic that is being measured.

Normal means

Select Normal means if the quality characteristic of interest is continuous and probably normally distributed.

Binomial proportions

Select Binomial proportions if the characteristic of interest is an attribute that is distributed following the binomial distribution. For example, this setting would be applicable when designing a sampling plan to determine the proportion defective in a batch.

Poisson frequencies

Select Poisson frequencies if the characteristic of interest is a relatively rare attribute. For example, this setting would be applicable when designing a sampling plan to determine the number of defects found in a batch.

Sample size estimation for binomial proportions and Poisson frequencies

Note that the sampling plans options in the Process Analysis module will use the normal approximation to the binomial and Poisson distributions in order to estimate required fixed sample sizes. These approximations are described in, for example, Duncan (1986), and are consistent with the approach used in quality control charting (see also Quality Control for additional details). Note that, usually, in power analysis applications in the biomedical sciences, the explicit formulas (instead of the normal approximations) are used, and those analyses may yield slightly different results. If your version of STATISTICA does not include the Statistica Power Analysis module, please contact Dellt or visit our web site at http://statistica.io for information about the availability of this module.

Test criterion

The Test criterion box contains three options: Two tailed, One-sided (right) test, and One-sided (left) test.

Two tailed

If you select Two tailed, the sampling plan is computed so as to detect a shift in either direction from the mean under H₀.

One-sided (right) test

If you select One-sided (right) test, the sampling plan is computed so as to detect an H₁ mean that is greater than H₀.

One-sided (left) test

If you select One-sided (left) test, the sampling plan is computed so as to detect an H₁ mean that is smaller than H₀.