document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1201376>Question 1201376</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A United Nations report shows the mean family income for Mexican migrants to the United States is $27,000 per year. A FLOC (Farm Labor Organizing Committee) evaluation of 25 Mexican family units reveals a mean to be $30,000 with a sample standard deviation of $10,000. Does this information disagree with the United Nations report? Apply the 0.01 significance level.\r<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 #835732 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=835732\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> population mean is assumed to be 27,000 per year.<BR>\n" );
document.write( "sample of 25 mexicans shows the sample mean to be equal to 20,000 with a sample standard deviation of 10,000.<BR>\n" );
document.write( "the standard error is equal to the sample standard deviation divided by the sample size = 10,000 / sqrt(25) = 10,000 / 5 = 2000.<BR>\n" );
document.write( "you would use the t-score for the test because your standard deviation is from the sample and not from the population.<BR>\n" );
document.write( "because you are looking at the mean of a sample, the standard error is used rather than the standard deviation.<BR>\n" );
document.write( "standard error = standard deviation / sqrt(sample size) = 2000 / sqrt(25) = 2000 / 5 = 400.<BR>\n" );
document.write( "the t-score formula is t = (x - m) / s<BR>\n" );
document.write( "t is the t-score<BR>\n" );
document.write( "x is the sample meaan<BR>\n" );
document.write( "m is the population  mean<BR>\n" );
document.write( "s is the standard error.<BR>\n" );
document.write( "t = (x - m) / becomes t = (30000 - 27000) / 400 = 7.5<BR>\n" );
document.write( "the critical t-score with 24 degrees of freedom (number of degrees of freedom equals sample size minus 1) is equal to 2.796939498.<BR>\n" );
document.write( "somce the test t-score is greater than the critical t-score, the results are significant and the conclusiomn is that the mean income is greater than 27,000. </SPAN>\n" );
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