document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=181606>Question 181606</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study,researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the<BR>\n" );
document.write( "inactive pill. (a) State the appropriate hypotheses. (b) Obtain a test statistic and p-value. Interpret the results at &#945; = .01. (c) Is normality assured? (d) Is the difference large enough to be important?<BR>\n" );
document.write( "(e) What else would medical researchers need to know before prescribing this drug widely? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #136251 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=136251\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study,researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). <BR>\n" );
document.write( "After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the inactive pill. <BR>\n" );
document.write( "-------------------------------------<BR>\n" );
document.write( "(a) State the appropriate hypotheses.<BR>\n" );
document.write( "Ho: p(placebo)-p(active) =0<BR>\n" );
document.write( "Ha: p(placebo)-p(active) >0<BR>\n" );
document.write( "--------------------------------<BR>\n" );
document.write( "57/2325 = 0.025  97/2081 = 0.047<BR>\n" );
document.write( "(b) Obtain a test statistic and p-value. <BR>\n" );
document.write( "z(0.047-0.025) = (0.022)/sqrt[(0.047*0.953)/2081 + (0.025*0.975)/2325)]=3.889<BR>\n" );
document.write( "---<BR>\n" );
document.write( "p-value = P(z>3.889) = 5.043x10^-5<BR>\n" );
document.write( "Interpret: There is a 0.00000005043% probability that test results could<BR>\n" );
document.write( "have provided stronger evidence for rejecting Ho.<BR>\n" );
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document.write( "Interpret the results at &#945; = .01.<BR>\n" );
document.write( "Since p-value is less than 1% reject Ho.<BR>\n" );
document.write( "The lovastatin is a better medicine than the placebo.<BR>\n" );
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document.write( "(c) Is normality assured? <BR>\n" );
document.write( "Check whatever normality conditions are required by your text.<BR>\n" );
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document.write( "(d) Is the difference large enough to be important?<BR>\n" );
document.write( "It is enormous.<BR>\n" );
document.write( "-------------------------------<BR>\n" );
document.write( "(e) What else would medical researchers need to know before prescribing this drug widely?<BR>\n" );
document.write( "I'll leave that to you.<BR>\n" );
document.write( "======================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );