- The mean yarn count of 200 samples is 20.46 Ne, and the standard deviation is 0.5. The tolerance limit for yarn count variation is 19.7 Ne to 21.22 Ne. Determine the off-count percentage.
- In a normal distribution, 10% of the yarn fault (thick/thin places/neps) is under 4mm in length, and 90% of the yarn is under 20 mm long. What are the mean and standard deviation of the distribution?
- The mean count of 100 yarn samples was found to be 40’s with an SD of 6’s Ne. How many tests are required to make at a 95% confidence limit, and an error in the yarn count of 2.56%?
- 4. A manufacturing company produces knitted sports goods. It was found that 2% of the goods produced were defective. What is the probability that in a shipment of 100 such goods, 4% or more will prove to be defective?
- A manufacturing company produces knitted sports goods. It is found that 2% of the goods produced are defective. What is the probability that in a shipment of 100 such goods 4% or more will prove to be defective?
- A mass of 150g was hung in turn from 250 pieces of a certain yarn, and 12 of the pieces broke. A load of 200g was then hung from the previously unbroken pieces and a further 213 pieces broke. Assume that yarn strength is distributed normally. Estimate the mean and standard deviation of the yarn strength.
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