document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=827862>Question 827862</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 4. Tennis-Warehouse recently conducted a study of long distance phone calls made by its employees. The study showed that the length of the calls has a mean of 3.2 minutes, a standard deviation of 0.50 minutes and it follows the normal probability distribution.  <BR>\n" );
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document.write( "(a) What portion of the calls was between 3.2 and 4 minutes?<BR>\n" );
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document.write( "(b) What portion of the calls was more than 4 minutes?\r<BR>\n" );
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document.write( "(c) What portion of the calls was between 4 and 4.5 minutes?\r<BR>\n" );
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document.write( "(d) What portion of the calls was between 3 and 4.5 minutes?<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 #498909 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=498909\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The study showed that the length of the calls has a mean of 3.2 minutes, a standard deviation of 0.50 minutes and it follows the normal probability distribution.<BR>\n" );
document.write( "For each of these problems:<BR>\n" );
document.write( "1st: Find the z-value of the figures<BR>\n" );
document.write( "2nd: Find the probability that z satisfies the condition of the problem:<BR>\n" );
document.write( "I'll do part \"a\":\r<BR>\n" );
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document.write( "(a) What portion of the calls was between 3.2 and 4 minutes?<BR>\n" );
document.write( "z(3.2) = (3.2-3.2)/0.5 = 0<BR>\n" );
document.write( "z(4) = (4-3.2)/0.5 = 0.8/0.5 = 1.6<BR>\n" );
document.write( "P(3.2< x <4) = P(0< z < 1.6) = normalcdf(0,1.6) = 0.4452<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.====================== <BR>\n" );
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document.write( "(b) What portion of the calls was more than 4 minutes? <BR>\n" );
document.write( "(c) What portion of the calls was between 4 and 4.5 minutes? <BR>\n" );
document.write( "(d) What portion of the calls was between 3 and 4.5 minutes?<BR>\n" );
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