document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1178780>Question 1178780</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Americans receive an average of 18 Christmas cards each year. Suppose the number of Christmas cards is normally distributed with a standard deviation of 5. Let X be the number of Christmas cards received by a randomly selected American. Round all answers to 4 decimal places where possible.\r<BR>\n" );
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document.write( "a. What is the distribution of X? X ~ N( ,)\r<BR>\n" );
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document.write( "b. If an American is randomly chosen, find the probability that this American will receive no more than 21 Christmas cards this year. <BR>\n" );
document.write( " (Round z-score up to 2 decimal places.)\r<BR>\n" );
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document.write( "c. If an American is randomly chosen, find the probability that this American will receive between 19 and 24 Christmas cards this year. <BR>\n" );
document.write( " (Round z-score up to 2 decimal places.)\r<BR>\n" );
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document.write( "d. 82% of all Americans receive at most how many Christmas cards? (Please enter a whole number) <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 #808444 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=808444\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> X~N(18, 25) mean, sigma^2<BR>\n" );
document.write( "z <(21-18)/5=3/5. That probability is 0.7257<BR>\n" );
document.write( "z will be between 1/5 and 6/5. That probability is 0.3057<BR>\n" );
document.write( "82% is a z of 0.9154<BR>\n" );
document.write( "0.9154=(x-18)/5<BR>\n" );
document.write( "x=18+4.58<BR>\n" );
document.write( "22.58 cards.<BR>\n" );
document.write( "At most it would be 22 cards.<BR>\n" );
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