Sampling is a sampling plan in accordance with the provisions randomly from the batch or process a small sample of individuals (as a sample) tests performed in accordance with the results of the sample test to determine a number or a process can be accepted. Sampling: Verify that the object is a number of products, product batch application of statistical theory to infer based on the sampling results received or not. But still test receive lots may contain non-conforming product, does not receive batches of course also includes qualified products. Sampling is generally used in the following circumstances:

    (1) destructive inspection, such as product reliability test, the product life testing, fatigue testing of materials, the strength of the part test. (2) large quantities of full inspection inspection of a lot of work, such as screws, pins, gaskets, resistors. (3) measurement of bulk or processed materials, such as coal, ore, cement, molten steel, the entire volume steel inspection. (4) does not apply to full inspection or full test uneconomical occasions.