document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=193283>Question 193283</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780073534961/algebrahomeworkh>Elementary Statistics</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> 19.) A biologist knows that the average length of a leaf of a certain full-grown plat is 4 inches. The standard deviation of the population is 0.6 inch. A sample of 20 leaves of that type of plant given a new type of plant food had an average lenght of 4.2 inches. Is there reason to believe that the new food is responsible for a change in the growth of the leaves? use &#945;=0.01. Find the 99% confidence interval of the mean. DO the results occur? Explain. Assume that the variable is approximately normally distributed.\r<BR>\n" );
document.write( "\n" );
document.write( "My answer, Ho:µ = 4 and H1:µ &#8800;4: C.V.= ±2.58<BR>\n" );
document.write( "           z=1.49; 3.85<µ<4.55; do not reject. There is not enough evidence to support the cail that the growth has change.  Is this correct?\r<BR>\n" );
document.write( "\n" );
document.write( "10.) The tennis Industry Association reported that 14% of tennis fans were female. If, in a sample of 30 tennis fans, 15 were female, do the results suggest that the percetage may have changed? use &#945; = 0.02.\r<BR>\n" );
document.write( "\n" );
document.write( "Please help me with this problems. Thanks.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #145165 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=145165\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A biologist knows that the average length of a leaf of a certain full-grown plat is 4 inches. The standard deviation of the population is 0.6 inch. A sample of 20 leaves of that type of plant given a new type of plant food had an average lenght of 4.2 inches. Is there reason to believe that the new food is responsible for a change in the growth of the leaves? use &#945;=0.01. Find the 99% confidence interval of the mean. DO the results occur? Explain. Assume that the variable is approximately normally distributed. <BR>\n" );
document.write( "My answer, Ho:µ = 4 and H1:µ &#8800;4: C.V.= ±2.58<BR>\n" );
document.write( "z=1.49; 3.85<µ<4.55; do not reject. There is not enough evidence to support the cail that the growth has change. Is this correct? <BR>\n" );
document.write( "-------<BR>\n" );
document.write( "Yes, if you are allowed to use a-scores for mean problems.<BR>\n" );
document.write( "Most texts require that you use t-scores.<BR>\n" );
document.write( "-----------------------------------------------------------<BR>\n" );
document.write( "10.) The tennis Industry Association reported that 14% of tennis fans were female. If, in a sample of 30 tennis fans, 15 were female, do the results suggest that the percentage may have changed? use &#945; = 0.02. <BR>\n" );
document.write( "Please help me with this problems. Thanks. <BR>\n" );
document.write( "Ho: p = 0.14<BR>\n" );
document.write( "H1: p is not equal to 0.14<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "test statistic: z(15/30) = ((0.5)-0.14)/sqrt[0.14*0.86/30] = 5.6826<BR>\n" );
document.write( "Critical value for 2-tail test with alpha = 0.02 : z= +/-2.326<BR>\n" );
document.write( "p-value: 2P(z > 5.6826) = 0.00000000665<BR>\n" );
document.write( "-------------<BR>\n" );
document.write( "Conclusion: since the test stat. is in the reject interval, reject Ho.<BR>\n" );
document.write( "===========================================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );