document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=740412>Question 740412</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Test the claim that the mean time Americans spend watching TV per day is 4.4 hours at the 0.10 level of significance. A random sample of 80 people had a mean time of 2.225 hours viewing per day and a standard deviation of 1.088 hours.\r<BR>\n" );
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document.write( "I have a hard time determining whether to use a z test or t test. Here I think it is a z test because the sample is over 30.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #451619 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=451619\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Test the claim that thee mean time Americans spend watching TV per day is 4.4 hours at the 0.10 level of significance. A random sample of 80 people had a mean time of 2.225 hours viewing per day and a standard deviation of 1.088 hours. <BR>\n" );
document.write( "I have a hard time determining whether to use a z test or t test. Here I think it is a z test because the sample is over 30. <BR>\n" );
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document.write( "Some texts use a t-test for ALL means testing.  Others use the t-test<BR>\n" );
document.write( "only for samples <= 30.  You'll have to check your text to see which <BR>\n" );
document.write( "way to go, or do it both ways.<BR>\n" );
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document.write( "Ho: u = 4.4(claim)<BR>\n" );
document.write( "Ha: u # 4.40<BR>\n" );
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document.write( "z(2.225) = (2.225-4.4)/1.088 = -1.9991<BR>\n" );
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document.write( "p-value = 2*P(z < -1.9991) = 2*normalcdf(-100,-1.9991) =  0.04560<BR>\n" );
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document.write( "Since the p-value is < 10%, reject Ho.<BR>\n" );
document.write( "The test results do not support the claim.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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