document.write( "Question 856507: A random sample of 250 students entering the university included 120 females, of whom 20 belonged to a minority group, 65 had averages over 80%, and 10 fit both categories. Among the 250 students, a total of 105 people in the sample had averages over 80%, and a total of 40 belonged to the minority group. Fifteen males in the minority group had averages over 80%
\n" ); document.write( "i) Given a person was a male from the minority group, what is the probability he had an average over 80%? ii) What is the probability that a person selected at random was male, did not come from the minority group, and had an average less than 80%? \n" ); document.write( "

Algebra.Com's Answer #516030 by Theo(13342) $\"\"$ $\"About$

You can put this solution on YOUR website!
if i got the counts right, these are the numbers;\r
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document.write( "                               female      male     total\r\n" );
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document.write( "students                         120        130       250\r\n" );
document.write( "black                             20         20        40\r\n" );
document.write( "white                            100        110       210\r\n" );
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document.write( "greater than 80%                  65         40        105\r\n" );
document.write( "black                             10         15         25\r\n" );
document.write( "white                             55         25         80\r\n" );
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document.write( "less than or equal to 80%         55         90        145\r\n" );
document.write( "black                             10          5         15\r\n" );
document.write( "white                             45         85        130\r\n" );
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\n" ); document.write( "\n" ); document.write( "answers to the questions:\r
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\n" ); document.write( "\n" ); document.write( "i) Given a person was a male from the minority group, what is the probability he had an average over 80%?\r
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\n" ); document.write( "\n" ); document.write( "20 males from a minoty group and 15 of them have 80% or higher so the probability is 15/20 = 3/4 = 75%
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\n" ); document.write( "\n" ); document.write( "ii) What is the probability that a person selected at random was male, did not come from the minority group, and had an average less than 80%? \r
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\n" ); document.write( "\n" ); document.write( "this would be a white male with an average less than 80%.
\n" ); document.write( "from the table, there are 85 of them.
\n" ); document.write( "the probability is therefore 85/250 = 34%\r
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