document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=927356>Question 927356</A>: <I><SPAN STYLE=\"word-break: break-all;\">  A city is interested in estimating the amount of time children spend on the internet <BR>\n" );
document.write( "each day. It is known the the time spent follows a normal distribution with standard<BR>\n" );
document.write( "deviation 35 minutes.<BR>\n" );
document.write( "(a) How many children would be needed to estimate the true mean amount of time<BR>\n" );
document.write( "spent on the internet to within 19 minutes with 95% confidence?<BR>\n" );
document.write( "(b) How many children would be needed to estimate the true mean amount of time<BR>\n" );
document.write( "spent on the internet to within 19 minutes with 96% confidence?<BR>\n" );
document.write( "(c) Only using your answer in (a), how many children are needed to estimate the<BR>\n" );
document.write( "true mean amount of time spent on the internet to within 18 minutes with 95%<BR>\n" );
document.write( "confidence?<BR>\n" );
document.write( "(d) What happened to your sample size from part (a) to part (b)? Explain.<BR>\n" );
document.write( "(e) Create a 90% confidence interval for the true mean amount of time spent on the<BR>\n" );
document.write( "internet.<BR>\n" );
document.write( "(f) Interpret your interval in (e).<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #562933 by </B><A HREF=/tutors/aboutme.mpl?userid=ewatrrr><B>ewatrrr(24785)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ewatrrr><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=ewatrrr><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=562933\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a) n = (zSD/ME)^2 = (1.96*35/19)^2 = 13.0359  0r 14<BR>\n" );
document.write( "b) n = (zSD/ME)^2 = (2.0537*35/19)^2 = 14.312 0r 15<BR>\n" );
document.write( "c) n > 14, n = (zSD/ME)^2 = (1.96*35/18)^2 = 14.5246  0r 15<BR>\n" );
document.write( "d) Sample size part b is Larger  due to  increased confidence Level.<BR>\n" );
document.write( "e) ME = 1.645(12) = 57.575  (round as directed)<BR>\n" );
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