document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1209659>Question 1209659</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 17​% adults favor the use of unmanned drones by police agencies. Twelve U.S. adults are randomly selected. Find the probability that the number of U.S. adults who favor the use of unmanned drones by police agencies is​ (a) exactly​ three, (b) at least​ four, (c) less than eight. \r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #849770 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52835)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=849770\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .<BR>\n" );
document.write( "17​% adults favor the use of unmanned drones by police agencies. Twelve U.S. adults are randomly selected. <BR>\n" );
document.write( "Find the probability that the number of U.S. adults who favor the use of unmanned drones by police agencies is​ <BR>\n" );
document.write( "(a) exactly​ three, <BR>\n" );
document.write( "(b) at least​ four, <BR>\n" );
document.write( "(c) less than eight. <BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;In the post by @CPhill, &nbsp;all calculations for part &nbsp;(b) &nbsp;are incorrect.\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The answer for part &nbsp;(b) &nbsp;is incorrect, too.\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Below I placed my correct calculations.\r<BR>\n" );
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document.write( "**(b) At least four:**\r\n" );
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document.write( "This means x = 4, 5, 6, ..., 12.  It's easier to calculate the complement and subtract from 1:\r\n" );
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document.write( "P(x ≥ 4) = 1 - P(x < 4)\r\n" );
document.write( "P(x ≥ 4) = 1 - [P(x = 0) + P(x = 1) + P(x = 2) + P(x = 3)]\r\n" );
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document.write( "*   P(x = 0) = (12C0) * (0.17)^0 * (0.83)^12 ≈ 0.10689\r\n" );
document.write( "*   P(x = 1) = (12C1) * (0.17)^1 * (0.83)^11 ≈ 0.26272\r\n" );
document.write( "*   P(x = 2) = (12C2) * (0.17)^2 * (0.83)^10 ≈ 0.29595\r\n" );
document.write( "*   P(x = 3) ≈ 0.201 (calculated above)\r\n" );
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document.write( "P(x ≥ 4) = 1 - (0.10689 + 0.26272 + 0.29595 + 0.201)\r\n" );
document.write( "P(x ≥ 4) = 1 - 0.867\r\n" );
document.write( "P(x ≥ 4) ≈ 0.133\r\n" );
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document.write( "Corrected.\r<BR>\n" );
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