document.write( "Question 1207885: Each packet of a certain cereal contains a small plastic model of one of five different dinosaurs; a
\n" ); document.write( "packet is equally likely to contain any one of the five dinosaurs. Find the probability that someone
\n" ); document.write( "buying six packets of the cereal will acquire models of their three favourite dinosaurs. Using inclusion and exclusion probability
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Algebra.Com's Answer #846011 by ikleyn(52800)\"\" \"About 
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\n" ); document.write( "Each packet of a certain cereal contains a small plastic model of one of five different dinosaurs; a
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document.write( "In this problem, we have random samples of 6 items from an unlimited pool of items of 5 different types mixed evenly.\r\n" );
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document.write( "Selection an item of one or another type at each trial is random; each type can be selected with the probability 1/5.\r\n" );
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document.write( "For us, the success at each random trial is to get randomly any item of some of 3 favorite types; \r\n" );
document.write( "so, the probability of success is 3/5 at each individual trial.\r\n" );
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document.write( "The number of trials is 6.\r\n" );
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document.write( "Thus, we have a Binomial distribution experiment with  6 trials, 3 success trials \r\n" );
document.write( "and probability of the individual success at each trial of 3/5.\r\n" );
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document.write( "Hence, to answer the question, use the standard formula of partial binomial distribution probability\r\n" );
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document.write( "    P = \"C%5B6%5D%5E3%2A%283%2F5%29%5E3%2A%281-3%2F5%29%5E%286-3%29\" = \"%28%286%2A5%2A4%29%2F%281%2A2%2A3%29%290.6%5E3%2A0.4%5E3\" = 0.27648 (rounded).\r\n" );
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document.write( "ANSWER.  \r\n" );
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\n" ); document.write( "\n" ); document.write( "The last instruction in this post \"Using inclusion and exclusion probability\" is IRRELEVANT and does not make any sense.\r
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\n" ); document.write( "\n" ); document.write( "These terms are never used in this area, so do not try to invent, to introduce and to use them. It is not a good style.\r
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