document.write( "Question 1025786: Seven percent of the items produced at a factory are defective. The quality control team selects a random sample of 25 items.
\n" ); document.write( "a. What is the probability that more than three items in the sample are defective?
\n" ); document.write( "b. If items are selected randomly until the first defective item is encountered, how many items, on average, will have to be sampled before the first defective item is found?
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Algebra.Com's Answer #641102 by robertb(5830) $\"\"$ $\"About$

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a. Let X = # of items that are defective. The r.v. X follows the binomial distribution.\r
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, to four decimal places. \r
\n" ); document.write( "\n" ); document.write( "b. Let X = the number of trials in getting the first defective item.
\n" ); document.write( "This r.v. follows the geometric distribution with support 1,2, 3, 4, 5,... .
\n" ); document.write( "The mean of the geometric distribution where the probability of success is p = 0.07 (in this case getting a defective item) is 1/p = 1/0.07 = 14.2857, or 14 items. \n" ); document.write( "

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