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# Twenty percent of all telephones of a certain type are

ISBN: 9780321629111 32

## Solution for problem 55E Chapter 3

Probability and Statistics for Engineers and the Scientists | 9th Edition

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Problem 55E

Twenty percent of all telephones of a certain type are submitted for service while under warranty. Of these, 60% can be repaired, whereas the other 40% must be replaced with new units. If a company purchases ten of these telephones, what is the probability that exactly two will end up being replaced under warranty?

Step-by-Step Solution:

Answer : Step 1 : Given twenty percent of all telephones of a certain type are submitted for service while under warranty. Of these, 60% can be repaired, whereas the other 40% must be replaced with new units. Let X be the number of phones submitted for service and Let R be be the number of telephones which are replaced after being submitted for service. We have the following distributions: X ~ Binomial (n = 10,p = 0.20)and X ~ Binomial (n = X,p = 0.40) x x x r Use the law of total probability to find the answer. Note that the first two probabilities in the sum are both zero, i.e., it is not possible to have. R=2 if x=0 or x=1. P(R = 2) = P R=2 P(X = 0) + P R=2 P(X = 1) + ... + P R=2 P(X = 10) ( X=0) (X=1 ) ( X=10) 10 R=2 P(R = 2) = P (X=x )P(X = x) x=2 10 x 2 102 10 x 10x P(R = 2) = ( )(p2) (1r p) ( x(p )x(1 p )x x=2 P(R = 2) = 0.1478070 Therefore the probability is 0.1478. Presumably, only phones that were submitted...

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##### ISBN: 9780321629111

Probability and Statistics for Engineers and the Scientists was written by and is associated to the ISBN: 9780321629111. This full solution covers the following key subjects: replaced, warranty, under, these, telephones. This expansive textbook survival guide covers 18 chapters, and 1582 solutions. The full step-by-step solution to problem: 55E from chapter: 3 was answered by , our top Statistics solution expert on 05/06/17, 06:21PM. The answer to “Twenty percent of all telephones of a certain type are submitted for service while under warranty. Of these, 60% can be repaired, whereas the other 40% must be replaced with new units. If a company purchases ten of these telephones, what is the probability that exactly two will end up being replaced under warranty?” is broken down into a number of easy to follow steps, and 54 words. Since the solution to 55E from 3 chapter was answered, more than 326 students have viewed the full step-by-step answer. This textbook survival guide was created for the textbook: Probability and Statistics for Engineers and the Scientists, edition: 9.

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