document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1191469>Question 1191469</A>: <I><SPAN STYLE=\"word-break: break-all;\"> There are 5 coins in a bag: 3 weighted coins with Pr[H]=8/9 and 2 fair coins. One is chosen at random and flipped 180 times. What is the expected number of H flipped? </SPAN>\n" );
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document.write( "If a fair coin is chosen and flipped 180 times, the expected number of heads will be 180(1/2) = 90.<br><BR>\n" );
document.write( "If a weighted coin is chosen and flipped 180 times, the expected number of heads will be 180(8/9) = 160.<br><BR>\n" );
document.write( "The probability that a fair coin is selected is 2/5; the probability that a weighted coin is selected is 3/5.<br><BR>\n" );
document.write( "The expected number of heads in the described experiment is then<br><BR>\n" );
document.write( "(2/5)(90)+(3/5)(160) = 36+96 = 132<br><BR>\n" );
document.write( "ANSWER: 132<br><BR>\n" );
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