document.write( "Question 1082432: Please help solve the following probability question.\r \n" );
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document.write( "The following mark distribution was extracted from a report prepared by the examiner for Statistics in 2014 for 382 students who wrote the exam.\r \n" );
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document.write( "Marks (%) Number of students \n" );
document.write( "10 - 20 30 \n" );
document.write( "20 - 30 45 \n" );
document.write( "30 - 40 85 \n" );
document.write( "40 - 50 92 \n" );
document.write( "50 - 60 80 \n" );
document.write( "60 - 70 40 \n" );
document.write( "70 - 80 8 \n" );
document.write( "80 - 90 2\r \n" );
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document.write( "Estimate variance and hence standard deviation for student marks in this exam. \n" );
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