document.write( "Question 1207541: 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( " \n" ); document.write( "

Algebra.Com's Answer #845480 by ikleyn(52803) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "A test consists of 10 multiple choice questions, each with five possible answers.
\n" ); document.write( "one of which is correct. To pass the test a student must get 60% or better on the test.
\n" ); document.write( "If a student randomly guesses, what is the probability that the student will pass the test.
\n" ); document.write( "~~~~~~~~~~~~~~~~~~~\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "This experiment is a binomial distribution with 10 trials.\r\n" );
document.write( "The probability of success in each individual trial is 1/5 = 0.2;\r\n" );
document.write( "the probability of fault is 4/5 = 0.8.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "They want you determine the probability of 6 or more successes of 10 trials.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "You may calculate P(6), P(7), P(8), P(9) and P(10) separately and then add.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It is really tedious exercise. Another way is to calculate this probability in one click, \r\n" );
document.write( "using an Excel function BINOM.DIST in the accumulative mode\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "    P = P(6) + P(7) + P(8) + P(9) + P(10) = 1 - BINOM.DIST(5, 10, 0.2, 1) = 0.006369.    ANSWER\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Notice that we need  P = P(6) + P(7) + P(8) + P(9) + P(10),  and we calculate it as \r\n" );
document.write( "\r\n" );
document.write( "the  COMPLEMENT  of  BINOM.DIST(5, 10, 0.2, 1)  to  1:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "    P(6) + P(7) + P(8) + P(9) + P(10) = 1 - (P(0) + P(1) + P(2) + P(3) + P(4) + P(5)).\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The last argument \"1\" of the function means \"the cumulative mode\".\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( "Solved.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );