document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=953334>Question 953334</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Is it possible to get a negative z-zore?<BR>\n" );
document.write( "the Philadelphia zoo reports that the mean life span of a Galápagos tortoise is 100 years. Assume that their life span follows a normal distribution with the mean= 100 years and standard deviation = 15 years.<BR>\n" );
document.write( "a) find the probability that a randomly chosen tortoise will live longer than 70 years. \r<BR>\n" );
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document.write( "z= 70-100<BR>\n" );
document.write( "    --------- = -2 <BR>\n" );
document.write( "         15 \r<BR>\n" );
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document.write( "P(z> -2) 1-0.0228= 0.9772. that's the answer i got but i'm not sure if i did it correctly. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #582173 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=582173\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> yes, it's possible to get a negative z-score.\r<BR>\n" );
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document.write( "if your actual score is less than the mean, you will get a negative z-score.\r<BR>\n" );
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document.write( "if your actual score is more than the mean, you will get a positive z-score.\r<BR>\n" );
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document.write( "if you actual score is the same as the mean, you will get a z-score of zero.\r<BR>\n" );
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document.write( "your question is:\r<BR>\n" );
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document.write( "the Philadelphia zoo reports that the mean life span of a Galápagos tortoise is 100 years. Assume that their life span follows a normal distribution with the mean = 100 years and standard deviation = 15 years.\r<BR>\n" );
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document.write( "a) find the probability that a randomly chosen tortoise will live longer than 70 years. \r<BR>\n" );
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document.write( "the formula for z-score is:\r<BR>\n" );
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document.write( "z = (x-m)/s\r<BR>\n" );
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document.write( "z is the z-score.<BR>\n" );
document.write( "x is the raw score<BR>\n" );
document.write( "m is the mean of the raw score<BR>\n" );
document.write( "s is the standard deviation of the raw score.\r<BR>\n" );
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document.write( "the formula becomes:\r<BR>\n" );
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document.write( "z = (70 - 100) / 15 which results in:\r<BR>\n" );
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document.write( "z = -2.\r<BR>\n" );
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document.write( "you're looking for the probability for having a z-score of -2 or greater.\r<BR>\n" );
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document.write( "the z-score of -2 tells you that 2.28% of the area under the normal distribution curve is to the left of that z-score.\r<BR>\n" );
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document.write( "this means that 1 - .0228 = .9772 = 97.72% of the area under the normal distribution curve is to the right of that x-score.\r<BR>\n" );
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document.write( "this means that the probability that a turtle will live longer than 70 years is equal to 97.72%.\r<BR>\n" );
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document.write( "you did good.<BR>\n" );
document.write( " </SPAN>\n" );
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