Stat 215 Quiz 5

Stat 215 Quiz 5 - standard deviation of the number of...

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Stat 215 Quiz 5 Module: Quiz , Exercise: Poisson Question What is the probability that a randomly chosen square yard of cloth contains no defects? Answer X = number of defects per square yard. P(X = 0) = 1/e = 0.3679 (using the Poisson probability function) Your Answer p(Y=0)= e^-1 = 0.36788 Grader Comments (none) Grade 2.0 (out of 2.0) Total 7.5 (out of 10.0) Question What is the probability that a randomly chosen square yard of cloth contains exactly 1 defect? Answer P(X = 1) = 1/e = 0.3679 (using the Poisson probability function) Your Answer P(Y=1) = 0.36787 Grader Comments (none) Grade 2.0 (out of 2.0) Total 7.5 (out of 10.0) Question What is the probability that a randomly chosen square yard of cloth contains 2 or more defects? Answer P(X >= 2) = 1 - P(X <= 1) = 1 - P(X=0 or X=1) = 1 - 2/e = 0.2642 (using Poisson pdf) Using the table: p(X >= 2) = 1 - P(X <= 1) = 1 - .736 = 0.264 Your Answer P = 0.1839 Grader Comments (none) Grade 0.0 (out of 2.0) Total 7.5 (out of 10.0) Question What are the expected (mean) number of defects per square yard and the
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Unformatted text preview: standard deviation of the number of defects per square yard? Answer E(X) = 1 and SD(X) = 1, where X is the number of defects per square yard. Your Answer mean = standard deviation = 1 Grader Comments (none) Grade 2.0 (out of 2.0) Total 7.5 (out of 10.0) Question Explain why the Poisson probability model is appropriate here. Answer Variable X counts the number of events (defects) in a unit of space (one square yard of material).There is no fixed upper limit on the number of defects that may occur in one square yard of material. If we assume the the events (defects) occur randomly and that the rate of occurrence (one per square yard) remains constant, then the Poisson probability model is appropriate. Your Answer Poisson is appropriate because the data is given as an event per unit. Grader Comments (none) Grade 1.5 (out of 2.0) Total 7.5 (out of 10.0)...
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Stat 215 Quiz 5 - standard deviation of the number of...

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