document.write( "Question 872856: Hello, I have the following problem.\r
\n" ); document.write( "\n" ); document.write( "Marks obtained by a number of students follows normal distribution with mean 65 and variance 25. If 3 students are taken at random, what is probability that exactly two of them will have marks over 70?\r
\n" ); document.write( "\n" ); document.write( "I am confused that how to find probability of \" 2 out of 3 students \" with given distribution of marks of students. Thanks \n" ); document.write( "

Algebra.Com's Answer #526477 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi
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document.write( "Students: P(z >(70-65)/25) = .2 (20% score over 70)\r
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document.write( "Sample: p(over 70) = .2,   n = 3
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document.write( "P(x = 2) = 3C2(.2)^2(.8)^1  0r    binompdf( 3, .2, 2)= .096   0r 9.6% chance \n" );
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