1. Suppose we are taking samples from a manufacturing process. In a sample of 1000 items, 127 were found to be defective. Calculate a 95% confidence interval for the defect rate of this process?
.127 +/- 0.01 .127 +/- 0.02 .127 +/- 0.05 .127 +/- 0.10
2. Assume the defect rate in the above problem is 12.7%. What is the probability of taking a group of 10 items off the assembly line and having none of the 10 items be defective?
0.104 0.257 0.375 0.631
3. An inspection process takes samples of 10 items from production batches of 100 units and rejects the batch if there are 2 or more defects. Sampling is done without replacement, but since the sample is only 10% of the batch size you can use the binomial for estimation. Using the binomial, what is the probability that a batch will PASS the test if the average defect rate is 5%?
0.315 0.599 0.914 0.988
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