What Is a User Error?

User risk is one of the basic concepts of sampling inspection. It is the probability of making a second type of error, that is, the probability of accepting an unqualified batch as a qualified batch in sampling inspection and recording it as .

User risk is

For example, if a product batch has a non-conforming product rate of p0.05, it is a non-conforming batch. The current product batch is composed of 400 pieces, of which 25 non-conforming products should be non-conforming batches, but the inspection should be based on one sampling. The plan (400, 30, 1) took 30 pieces for inspection and found that there was only one non-conforming product. According to the plan, the product batch should be accepted. This made a second type of error, and the non-conforming batch was regarded as a qualified batch And received, so the user suffers. In order not to make users often suffer, when formulating a sampling inspection plan, the user risk should generally not be too large, and a number between 0.05 and 0.20 is often taken. ^[1]

cannot be determined in advance, and its size is affected by the following factors:

(1) The distance between the actual value and the assumed value of the parameter. The larger the distance, the smaller the value.

(2) a value. The larger the a value, the smaller the value.

In the actual situation, it is necessary to reduce the value of while specifying a, usually by increasing

(Typeerror)

The second type of error is also called "mouth error", "acceptance false error", "type II error". Hypothesis testing term. Contrast with "the first type of error".

In order to accept the error of the null hypothesis when performing the hypothesis test.

Since the test statistic is a random variable and has certain volatility, sometimes the original hypothesis H ₀ is incorrect. Under normal circumstances, the calculated statistic still has a certain probability that falls into the acceptance range, and thus incorrectly accepts the original Assume H ₀ .