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Where can I find charts or how do I figure the sample size for a 98% confidence for a double sampling plan for a lot of 330 items?

First, a point of clarification. Physical inventory accuracy rate and confidence level have different meanings. The physical inventory accuracy rate required by DoDI 5000.64 is the mandatory measure of how closely the inventory records and actual physical inventory counts must match. GAO-02-447G Best Practices in Inventory Counts provides the formula below forcalculating the inventory record accuracy rate.

Number of accurate items or records x 100% = record accuracy rate
Number of items or records counted

The confidence level is directly related to sampling. It is the probability that the sample is characteristically representative of the population (lot) from which it was selected. Use of 90%, 95%, or 97% confidence levels are both acceptable and prevalent in the performance of property management system analyses as well as other various forms of testing and inspecting. We are unaware of an existing 98% confidence double sampling plan table. If based on your objective you believe it is necessary to use a 98% confidence double sampling plan, it appears that you would have to design it. The hyperlinks below include sample size calculators (that allow you to enter any confidence level that you choose) and information that might assist you in designing a sampling plan.

https://www.itl.nist.gov/div898/handbook/pmc/section2/pmc24.htm
https://www.itl.nist.gov/div898/handbook/pmc/section2/pmc231.htm
https://www.omicsonline.org/open-access/determination-of-lot-size-in-theconstruction-of-six-sigma-based-doublesampling-plans-.php?aid=16355

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