document.write( "Question 979310: A student takes a 10-question, multiple-choice exam with three choices for each question and guesses on each question. Find the probability of guessing exactly 2 out of 10 correctly. \n" ); document.write( "
Algebra.Com's Answer #600585 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
A student takes a 10-question, multiple-choice exam with three choices for each
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document.write( "The formula for getting exactly x successes oout of n trials, when the\r\n" );
document.write( "probability of getting 1 success in 1 trial is p, is\r\n" );
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document.write( "\"nCx%2Ap%5Ex%2A%281-p%29%5E%28n-x%29\"\r\n" );
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document.write( "Here n=10 questions, p = \"1%2F10\" = 0.1\r\n" );
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document.write( "\"10C2%2A%280.1%29%5E2%2A%281-0.1%29%5E%2810-2%29\"\r\n" );
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document.write( "\"%28%2810%2A9%29%2F%282%2A1%29%29%2A%280.01%29%2A%280.9%29%5E8\"\r\n" );
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document.write( "\"45%2A%280.01%29%2A0.43046721\"\r\n" );
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document.write( "\"0.1937102445\"\r\n" );
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document.write( "You can also get it on a TI graphing calculator:\r\n" );
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document.write( "2nd, VARS, scroll down to binompdf(, ENTER\r\n" );
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document.write( "10 trials, p is 0.1, x value is 2\r\n" );
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document.write( "binompdf(10,0.1,2)  ENTER\r\n" );
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document.write( "Or use a binomial table if you have one.\r\n" );
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document.write( "Edwin
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