document.write( "Question 270297: A test consists of 10 multiple choice questions, each with five possible answers, one of which is correct. To pass the test a student must get 60% or better on the test. If a student randomly guesses, what is the probability that the student will pass the test? \n" ); document.write( "
Algebra.Com's Answer #198060 by Edwin McCravy(20056)\"\" \"About 
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A test consists of 10 multiple choice questions, each with five possible answers, one of which is correct. To pass the test a student must get 60% or better on the test. If a student randomly guesses, what is the probability that the student will pass the test?
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document.write( "This is a binomial probability problem with\r\n" );
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document.write( "n = 10 independent trials.\r\n" );
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document.write( "p = \"1%2F5=.20\", the probability of getting 1 answer right in 1 trial.\r\n" );
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document.write( "We want the probability of 6 or more successful (lucky) choices.\r\n" );
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document.write( "We will find the probability of the complement event and subtract \r\n" );
document.write( "from 1.\r\n" );
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document.write( "The complement event is the event of guessing 5 or fewer answers\r\n" );
document.write( "correct.\r\n" );
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document.write( "You have a table of cumulative binomial probabilities in the back of your \r\n" );
document.write( "book, like the one below, for the probabilities of x or fewer successful\r\n" );
document.write( "choices. Find the one which is headed n=10. Then find\r\n" );
document.write( "the column headed p = .20 and go down until you are in line with\r\n" );
document.write( "x = 5 on the far left.  There you read 0.994, which I have colored red below.  \r\n" );
document.write( "So your desired probability is gotten by subtracting 1 - 0.994 getting 0.006. \r\n" );
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document.write( "That's the answer 0.006.\r\n" );
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document.write( " n = 10 \r\n" );
document.write( " p   .01   .05   .10   .20   .25   .30   .40   .50   .60   .70   .75   .80   .90   .95   .99\r\n" );
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document.write( " x \r\n" );
document.write( " 0 0.904 0.599 0.349 0.107 0.056 0.028 0.006 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 \r\n" );
document.write( " 1 0.996 0.914 0.736 0.376 0.244 0.149 0.046 0.011 0.002 0.000 0.000 0.000 0.000 0.000 0.000 \r\n" );
document.write( " 2 1.000 0.988 0.930 0.678 0.526 0.383 0.167 0.055 0.012 0.002 0.000 0.000 0.000 0.000 0.000 \r\n" );
document.write( " 3 1.000 0.999 0.987 0.879 0.776 0.650 0.382 0.172 0.055 0.011 0.004 0.001 0.000 0.000 0.000 \r\n" );
document.write( " 4 1.000 1.000 0.998 0.967 0.922 0.850 0.633 0.377 0.166 0.047 0.020 0.006 0.000 0.000 0.000 \r\n" );
document.write( " 5 1.000 1.000 1.000 0.994 0.980 0.953 0.834 0.623 0.367 0.150 0.078 0.033 0.002 0.000 0.000 \r\n" );
document.write( " 6 1.000 1.000 1.000 0.999 0.996 0.989 0.945 0.828 0.618 0.350 0.224 0.121 0.013 0.001 0.000 \r\n" );
document.write( " 7 1.000 1.000 1.000 1.000 1.000 0.998 0.988 0.945 0.833 0.617 0.474 0.322 0.070 0.012 0.000 \r\n" );
document.write( " 8 1.000 1.000 1.000 1.000 1.000 1.000 0.998 0.989 0.954 0.851 0.756 0.624 0.264 0.086 0.004 \r\n" );
document.write( " 9 1.000 1.000 1.000 1.000 1.000 1.000 1.000 0.999 0.994 0.972 0.944 0.893 0.651 0.401 0.096 \r\n" );
document.write( "10 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 \r\n" );
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document.write( "We can also show you how to find it using your TI-83 or 84 calculator.\r\n" );
document.write( "It can also be done by formula, although thst would take a lot of\r\n" );
document.write( "time.  I think your teacher intended that you use the binomial tables.\r\n" );
document.write( "Edwin
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