document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=152632>Question 152632</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The probability is 1 in 4,000,000 that a single auto trip in the United States will result in a fatality. Over a lifetime, an average U.S. driver takes 50,000 trips. (a) What is the probability of a fatal accident over a lifetime? Hint: Assume independent events. Why might the assumption of the independence be violated? (b) Why might a driver be tempted not to use a seat belt “just on this trip”?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #112197 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=112197\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=%281%2F4000000%29%5E50000 ALIGN=MIDDLE  ALT=\"P=%281%2F4000000%29%5E50000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=%282.5x10%5E%28-7%29%29%5E50000 ALIGN=MIDDLE  ALT=\"P=%282.5x10%5E%28-7%29%29%5E50000\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "a) That's a pretty small number, almost zero. Even just taking ten trips, the probability is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9.5x10%5E%28-67%29 ALIGN=MIDDLE  ALT=\"9.5x10%5E%28-67%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >. But it's not zero. There are assumptions made about an average trip. The assumption doesn't take into account length of trip, speed of the trip, seatbelts on or off, how safe your car is, daytime/nightime, traffic congestion, urban/rural, weather conditions, number of airbags, etc. A 12 hour trip on a high speed freeway in Nome, Alaska probably has a higher likelihood of fatality than a 3 minute trip through a school zone in St. Louis, Missouri.<BR>\n" );
document.write( "b) The probability is so small, it shouldn't matter, but it does. <BR>\n" );
document.write( "On average, wearing a seatbelt increases the chances of surviving a crash, just like wearing a helmet while riding a bicycle or motorcycle.<BR>\n" );
document.write( "That doesn't mean, strap on the seat belt and drive 100 mph into a brick wall though, because those odds and the laws of physics are against you. <BR>\n" );
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