document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=195486>Question 195486</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780072966930/algebrahomeworkh></A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3.02. For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard deviation of $2.14. The means appear to be very close, but not the variances. At &#945; = .05, is there a difference in variances? Show all steps clearly, including an illustration of the decision rule. (Data are from a project by statistics students Kim Dyer, Amy Pease, and Lyndsey Smith.) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #146621 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=146621\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3.02. <BR>\n" );
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document.write( "For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard deviation of $2.14. <BR>\n" );
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document.write( "The means appear to be very close, but not the variances. At &#945; = .05, is there a difference in variances? Show all steps clearly, including an illustration of the decision rule.<BR>\n" );
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document.write( "Ho: variance1 = variance 2<BR>\n" );
document.write( "H1: variance 1 is not equal to variance 2 <BR>\n" );
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document.write( "test statistic: F = 3.02^2/2.14^2 = 1.9915...<BR>\n" );
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document.write( "alpha = 5%<BR>\n" );
document.write( "numerator df = 24 (not on the F chart so use df=25)<BR>\n" );
document.write( "denominator df = 25<BR>\n" );
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document.write( "Use Appendix F to find the critical values: (p. 288)<BR>\n" );
document.write( " Critical F value 2.23<BR>\n" );
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document.write( "Conclusion: Since the test statistic is not in the reject interval,<BR>\n" );
document.write( "Fail to reject Ho.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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