# Statistical Process Control Help

1. A medical supplies company buys its supplies in bulk and redistributes them to doctor's offices and clinics. They receive thermometers in lots of 500 from the vendor. They are considering a sampling plan of n=50 and c=1.

a. Develop a OC curve for this sampling plan. (Use Poisson Tables)

b. If an incoming lot has 5% defectives, what will be the probability of accepting the lot.

c. Determine the producer's risk if the AQL is 2%

d. Determine the consumer's risk if the LTPD is 14%

e. Develop a curve for AOQ and determine the value of AOQL.

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1. A medical supplies company buys its supplies in bulk and redistributes them to doctor's offices and clinics. The receive thermometers in lots of 500 from the vendor. They are considering a sampling plan of n = 50 and c = 1.

a. Develop an OC curve for this sampling plan. (Use Poisson Tables)

We assume that the lot size N = 500 is very large, as compared to the sample size n = 50, so that removing the sample doesn't significantly change the remainder of the lot, no matter how many defects are in the sample. Then the distribution of the number of defectives, d, in a random sample of n items is approximately Poisson with parameters n and p, where p is the fraction of defectives per lot.

Steps to develop an OC curve:

• Find your sample size, n. Here, n = 50

• Find your fraction defect p. Take p = 0.01, 0.02, 0.03, ......

• Multiply n*p

• Take c = d = 1

• From a Poisson table find your P(c)

The OC curve calculations are given ...

#### Solution Summary

This solution provides step by step calculations and graphs for developing curves and determining producer's and consumer's risks.