document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=130021>Question 130021</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This is not in a textbook - Can you please help??\r<BR>\n" );
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document.write( "Let us assume that average gas prices per gallon of unleaded gasoline in U.S. are normally distributed with the mean of $2.89 and the standard deviation of $0.05. Your neighborhood gas station charges $3.13 per gallon. You suspect the station owner charges too much and wish to determine whether there is a statistically significant difference between his price and the national average. Perform the z-test of hypothesis on the 0.05 level of significance. What is the conclusion? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #94982 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=94982\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let us assume that average gas prices per gallon of unleaded gasoline in U.S. are normally distributed with the mean of $2.89 and the standard deviation of $0.05. Your neighborhood gas station charges $3.13 per gallon. You suspect the station owner charges too much and wish to determine whether there is a statistically significant difference between his price and the national average. Perform the z-test of hypothesis on the 0.05 level of significance. What is the conclusion?<BR>\n" );
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document.write( "Ho:mu = 2.89<BR>\n" );
document.write( "Ha: mu > 2.89<BR>\n" );
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document.write( "Critical value for one-tail z-test and alpha = 5%: z = 1.645<BR>\n" );
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document.write( "Test statistic:<BR>\n" );
document.write( "z(3.13) = (3.13-2.89)/[0.05] = 4.8<BR>\n" );
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document.write( "Sice the test statistic is greater than the critical value,<BR>\n" );
document.write( "Reject Ho. There is significant statistical evidence that the<BR>\n" );
document.write( "local gas station is overcharging.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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