document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1161755>Question 1161755</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Eight chemical elements do not have isotopes (different forms of the same element having the same atomic number but different atomic weights). A random sample of 30 of the elements that do have isotopes showed a mean number of 19.63 isotopes per element, and the population has a standard deviation of 18.73. Estimate the true mean number of isotopes for all elements with isotopes with 90% confidence. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #785424 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=785424\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> half-interval is z*sigma/sqrt(n)=1.645 (for 90% CI)*18.73/sqrt(30)=5.63<BR>\n" );
document.write( "that is added to and subtracted from the sample mean.<BR>\n" );
document.write( "(14.00, 25.26) </SPAN>\n" );
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