document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1124583>Question 1124583</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The Better Business Bureau settles 75% of complaints it receives involving new car dealers. Suppose a sample of 160 complaints involving new car dealers is selected.\r<BR>\n" );
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document.write( "Find the probability that Better Business Bureau settles less than 129 of these complaints. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #740979 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=740979\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> mean is 0.75<BR>\n" );
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document.write( "we do not know the standard deviation of the population, so we will use the standard error<BR>\n" );
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document.write( "standard error = square root(0.75 * (1-0.75) / 160) = 0.0342<BR>\n" );
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document.write( "the sample size is greater than 30, so we can use the normal distribution<BR>\n" );
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document.write( "129/160 is approximately 0.8062<BR>\n" );
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document.write( "we want the probability that X is less than 0.8062<BR>\n" );
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document.write( "z-score = (0.8062 - 0.75)/0.0342 is approximately 1.64<BR>\n" );
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document.write( "using table of z-scores, we find the probability associated with z-score of 1.64<BR>\n" );
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document.write( "Probability ( X < 0.8062 ) = 0.9495<BR>\n" );
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