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4.33. An inspector counts the surface-finish defects in dishwashers. A random sample of five dishwashers contains three such defects. Is there reason to conclude that the mean occurrence rate of surface-finish defects per dishwasher exceeds 0.5? Use the results of part (a) of Exercise 4.32 and assume that α = 0.05.
4.32. Nonconformities occur in glass bottles according to a Poisson distribution. A random sample of 100 bottles contains a total of 11 nonconformities.
- (a) Develop a procedure for testing the hypothesis that the mean of a Poisson distribution λ equals a specified value λ0. Hint: Use the normal approximation to the Poisson.
- (b) Use the results of part (a) to test the hypothesis that the mean occurrence rate of nonconformities is λ = 0.15. Use α = 0.01.
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