document.write( "Question 357981: The probability that a student is late for statistics class is .2. There are 30 classes during the semster. \r
\n" ); document.write( "\n" ); document.write( " A. Find the probability that the student will be late exactly 5 times.
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\n" ); document.write( " B. Find the probability that he will be late fewer than 3 times.\r
\n" ); document.write( "\n" ); document.write( " C. Find the average number of times he will be late. \r
\n" ); document.write( "\n" ); document.write( " D. Find the standard deviation of the number of times he will be late. \n" ); document.write( "

Algebra.Com's Answer #255538 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi,\r
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document.write( "Note: The probability of x successes in n trials is: 
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document.write( "P = nCx* * where p and q are the probabilities of success and failure 
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document.write( "respectively. In this case  p(late) = .2 and q = .8
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document.write( "nCx = \r
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document.write( "A. Find the probability that the student will be late exactly 5 times.
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document.write( "P = 30C5* *\r
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document.write( "B. Find the probability that he will be late fewer than 3 times.
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document.write( "P( 0 lates) + P(1 lates) + P(late twice)\r
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document.write( "C. Find the average number of times he will be late. 
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document.write( "Mean = n*p = 30*(.2) = 6 times
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document.write( "D. Find the standard deviation of the number of times he will be late.
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document.write( "Definition of standard deviation =  =  \n" );
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