document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=450368>Question 450368</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In 1992, the FAA conducted 30,000 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1100 were positive. (a)	Construct a 95 percent confidence interval for the population proportion of positive drug tests. ..<BR>\n" );
document.write( "I have this as the answer but not sure if I did it correctly..<BR>\n" );
document.write( "N= positive tests / O=number of applicants tested / P= proportioned sample<BR>\n" );
document.write( "P=	n/o<BR>\n" );
document.write( "P=1100/30,000=11/300=0.036<BR>\n" );
document.write( "A standard error of p = SE(p) =(0.036*(1-0.036)/30000) = 0.11566\r<BR>\n" );
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document.write( "and I have to also answer...(b)	May you assume that this is a normal distribution?  (Check the normality of your proportion!)\r<BR>\n" );
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document.write( "Can you advise what formula to use if I have this wrong, please. I have only one more day to figure this///and thank you!\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 #309864 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=309864\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In 1992, the FAA conducted 30,000 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1100 were positive. (a) Construct a 95 percent confidence interval for the population proportion of positive drug tests. ..<BR>\n" );
document.write( "I have this as the answer but not sure if I did it correctly..<BR>\n" );
document.write( "N= positive tests / O=number of applicants tested / P= proportioned sample<BR>\n" );
document.write( "P= n/o<BR>\n" );
document.write( "P=1100/30,000=11/300=0.036<BR>\n" );
document.write( "A standard error of p = SE(p) =(0.036*(1-0.036)/30000) = 0.11566 <BR>\n" );
document.write( "and I have to also answer...(b) May you assume that this is a normal distribution? (Check the normality of your proportion!) \r<BR>\n" );
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document.write( "Can you advise what formula to use if I have this wrong, please. I have only one more day to figure this///and thank you! \r<BR>\n" );
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document.write( "If you are rounding to 2 decimal places you probably should<BR>\n" );
document.write( "use p-hat = 0.37 for your sample proportion.<BR>\n" );
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document.write( "SE = z*sqrt[pq/n]<BR>\n" );
document.write( "SE = 1.96*sqrt[0.37*0.63/30000] = 0.00546..<BR>\n" );
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document.write( "95% CI: 0.37-0.00546 < p < 0.37+0.00546<BR>\n" );
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document.write( "Also: I ran a 1-PropZInt on my TI-84 and got this same answer.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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