document.write( "Question 1079155: In a Gallop Poll conducted January 30 – February 2, 2008, 43% of 18-29 year olds said that they were worried about retirement. Find the probability that out of 15 college students ages 18 – 19:
\n" ); document.write( " (a) Exactly 1 worried about retirement.
\n" ); document.write( " (b) Fewer than 5 worried about retirement.
\n" ); document.write( " (c) At least 10 worried about retirement.
\n" ); document.write( " (d) Between 8 and 10 inclusively are worried about retirement.
\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #693509 by Boreal(15235) $\"\"$ $\"About$

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15 ways to choose 1, probability is 0.43 and the other 14 have a probability of .57 each.
\n" ); document.write( "multiply the three.
\n" ); document.write( "=0.0025
\n" ); document.write( "Fewer than 5:
\n" ); document.write( "need 0,2,4,3
\n" ); document.write( "0 is .43^15=3 x 10^-6, will ignore
\n" ); document.write( "2 is 15C2*0.43^2*0.57^13. notice how the exponents add to 15.
\n" ); document.write( "=0.0130
\n" ); document.write( "3 is 0.0426
\n" ); document.write( "4 is 0.0963
\n" ); document.write( "Sum is 0.1544. Not surprising, since the expected value is between 6 and 7
\n" ); document.write( "8 is 0.1470
\n" ); document.write( "9 is 0.0863
\n" ); document.write( "10 is 0.0390
\n" ); document.write( "inclusive is 0.2723
\n" ); document.write( "For at least 10
\n" ); document.write( "15 is <0.0001
\n" ); document.write( "14 is 0.0001
\n" ); document.write( "13 is 0.0006
\n" ); document.write( "12 is 0.0034
\n" ); document.write( "11 is 0.0134
\n" ); document.write( "That group is 0.0565 \n" ); document.write( "

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