document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=277743>Question 277743</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive. <BR>\n" );
document.write( "(a) Construct a 95 percent confidence interval for the population proportion of positive drug tests. <BR>\n" );
document.write( "(b) Why is the normality assumption not a problem, despite the very small value of p?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #202155 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=202155\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive.<BR>\n" );
document.write( "---<BR>\n" );
document.write( "sample proportion = 1143/86991 = 0.013<BR>\n" );
document.write( "standard error = E = 1.96sqrt(0.013*0.987/86991) = 0.000753<BR>\n" );
document.write( "------------------- <BR>\n" );
document.write( "(a) Construct a 95 percent confidence interval for the population proportion of positive drug tests.<BR>\n" );
document.write( "95% CI: 0.013-0.000753 < p < 0.013+0.000753<BR>\n" );
document.write( "95% CI: 0.01222 < p < 0.013753<BR>\n" );
document.write( "====================================<BR>\n" );
document.write( " <BR>\n" );
document.write( "(b) Why is the normality assumption not a problem, despite the very small value of p?<BR>\n" );
document.write( "I'll leave that to you.<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. <BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );