document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=414467>Question 414467</A>: <I><SPAN STYLE=\"word-break: break-all;\"> CRA CDs, Inc. wants the mean lengths of the “cuts” on a CD to be 135 seconds (2 minutes and 15 seconds). This will allow the disk jockeys to have plenty of time for commercials within each 10-minute segment. Assume the distribution of the length of the cuts follows the normal distribution with a standard deviation of 8 seconds. Suppose we select a sample of 16 cuts from various CDs sold by CRA CDs, Inc. What can we say about the shape of the distribution of the sample mean? <BR>\n" );
document.write( "A. What can we say about the shape of the distribution of the sample mean?<BR>\n" );
document.write( "B. What is the standard error of the mean?<BR>\n" );
document.write( "C. What percent of the samples will be greater than 128 minutes?<BR>\n" );
document.write( "D. What percent of the sample means will be greater than 128 but less than 140 minutes. \r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #290696 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=290696\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> CRA CDs, Inc. wants the mean lengths of the “cuts” on a CD to be 135 seconds (2 minutes and 15 seconds). This will allow the disk jockeys to have plenty of time for commercials within each 10-minute segment. Assume the distribution of the length of the cuts follows the normal distribution with a standard deviation of 8 seconds. Suppose we select a sample of 16 cuts from various CDs sold by CRA CDs, Inc. What can we say about the shape of the distribution of the sample mean? <BR>\n" );
document.write( "A. What can we say about the shape of the distribution of the sample mean?<BR>\n" );
document.write( "mean of the sample means = 135 seconds<BR>\n" );
document.write( "std of the sample means = 8/sqrt(16) = 2<BR>\n" );
document.write( "---------<BR>\n" );
document.write( "B. What is the standard error of the mean?<BR>\n" );
document.write( "2 seconds<BR>\n" );
document.write( "-----------<BR>\n" );
document.write( "C. What percent of the samples will be greater than 128 seconds?<BR>\n" );
document.write( "50%<BR>\n" );
document.write( "------<BR>\n" );
document.write( "D. What percent of the sample means will be greater than 128 but less than 140 minutes. <BR>\n" );
document.write( "z(128) = 0<BR>\n" );
document.write( "z(140) = (140-128)/2 = 6<BR>\n" );
document.write( "----<BR>\n" );
document.write( "P(128 <= x <= 140) = P(0<= z <6) = 0.5000<BR>\n" );
document.write( "=============================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "=============\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );