document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=483482>Question 483482</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 2.	The new Twinkle bulb has a standard deviation of 35 hours. A random sample of 50 light bulbs is selected from inventory. The sample mean was found to be 550 hours<BR>\n" );
document.write( "* can u show me how to get the answers also with work?\r<BR>\n" );
document.write( "\n" );
document.write( "a.	What is the margin of error [E] for a 90% confidence interval? Round your answer to the nearest hundredths (5 points)\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "b.	Construct a 90% confidence interval for the mean life of all Twinkle bulbs. (5 points)   <BR>\n" );
document.write( " \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "3. 	A standard placement test has a mean of 115 and a standard deviation of 10. What is the minimum sample size required if we want to construct the 90% confidence interval with the margin of error of 2 points?\r<BR>\n" );
document.write( "\n" );
document.write( "(<BR>\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 #330889 by </B><A HREF=/tutors/aboutme.mpl?userid=edjones><B>edjones(8007)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=edjones><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=edjones><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=330889\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 3)<BR>\n" );
document.write( "mean+-alpha/2(s/sqrt(n)=mean+-2<BR>\n" );
document.write( "+-1.645(s/sqrt(n)=+-2 Subtract the mean from each side.<BR>\n" );
document.write( "+-(1.645*10)/sqrt(n)=+-2<BR>\n" );
document.write( "+-2sqrt(n)=+-16.45<BR>\n" );
document.write( "+-sqrt(n)=+-8.225<BR>\n" );
document.write( "n=67.65 square each side.<BR>\n" );
document.write( "n=68<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Ed<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );