document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1183649>Question 1183649</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 4)	The strength limit of a specific type of a cable is random variable with mean value of 1500 kg and standard deviation 175 kg. The factory that manufactures this type of cables claims that they improved the materials that they used and the new resistance limit of the cable has increased. We randomly chose a sample of 50 cables and the mean strength limit was 1570 kg. If the strength limit in the specific type of cable is normally distributed with a significance level of 0.05, can we state that the claim of the manufacture factory is true? Justify your answer.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #814085 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=814085\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Ho: strength <=1500<BR>\n" );
document.write( "Ha: strength >1500<BR>\n" );
document.write( "alpha=0.05 p{reject Ho|Ho true}<BR>\n" );
document.write( "test stat is z<BR>\n" );
document.write( "reject Ho for z>1.645<BR>\n" );
document.write( "calculation is z=(x-mean)/sigma/sqrt(n)<BR>\n" );
document.write( "=70/(175/sqrt(50))<BR>\n" );
document.write( "=2.83<BR>\n" );
document.write( "reject Ho and conclude the claim is correct, the strength is greater.<BR>\n" );
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document.write( "</TD></TR></TABLE>\n" );