document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1052856>Question 1052856</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help with this:\r<BR>\n" );
document.write( "\n" );
document.write( "Assume the SAT test scores are normally distributed with a mean of 500 and a standard deviation of 100. Please show all work. \r<BR>\n" );
document.write( "\n" );
document.write( "(a) Consider all random samples of 64 test scores. What is the standard deviation of the sample means?\r<BR>\n" );
document.write( "\n" );
document.write( "(b) What is the probability that 64 randomly selected test scores will have a mean test score that is between 475 and 525?\r<BR>\n" );
document.write( "\n" );
document.write( "Thank you for your help!<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 #668165 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=668165\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The standard deviation of the sample means is the original sd/sqrt(n) the sample size<BR>\n" );
document.write( "That would be 100/sqrt(64)=100/8=12.5<BR>\n" );
document.write( "The probability 64 randomly selected test scores will be between 475 and 525 is the probability z is between -2 and 2, or 0.9545.  \<BR>\n" );
document.write( "z=(x-mean)/sd<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );