Online Statistical Calculators for Acceptance Sampling and Quality Control
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Check out Practical Acceptance Sampling: A Hands-On Guide, Second Edition. Written by Prof. Galit Shmueli (creator of SQC Online), the book is a concise introduction to the inspection of products and services for quality assurance using statistically-based sampling plans.
Yes. Applying a constant plan that does not take into account the history of batches is useless. The MIL-STD-105E switching rules and MIL-STD-1235C switching rules are an integral part of the sampling scheme.
Absolutely! Although the military standard itself was phased out in 1989, it's civilian counterparts, ANSI Z1.4 or ISO 2859 (which are essentially the same) still exist. In practice these sampling plans are widely used by many industries.
Yes. Some of our users apply acceptance sampling to processes such as auditing applications, checking errors on invoices, etc.
The problem lies in correctly using the tables. We suggest reading the standards carefully, and especially the legend and footnotes at the bottom of the particular table.
One common mistake, when arrows are present in the tables, is not adjusting the sample size according to the arrow. This is just one example.
Using our calculators is a safer alternative to the error-prone usage of the printed standards.
Here's more information about acceptance sampling and control charts.
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Quality has to be caused, not controlled.