Author Question: If the population standard deviation of the lifetime of washing machines is estimated to be 900 ... (Read 91 times)

dmcintosh

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If the population standard deviation of the lifetime of washing machines is estimated to be 900 hours, how large a sample must be taken in order to be 97 confident that the margin of error will not exceed 100 hours?

Question 2

The quality control department of a company has decided to select a sample of 20 items from each shipment of goods it receives and inspect them for defects. It has been decided that if the sample contains no defective parts, the entire lot will be accepted.
 a. What is the probability of accepting a lot that contains 10 defective items?
  b. What is the probability of accepting a lot that contains 5 defective items?
  c. What is the probability of rejecting a lot that contains 15 defective items?



FergA

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Answer to Question 1

382

Answer to Question 2

a. 0.1216
b. 0.3585
c. 0.9612



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