document.write( "Question 1081764: The average age of Amtrak passenger train cars is 19.4 years. If the distribution of ages is normal and 19% of the cars are older than 21.7 years, find the standard deviation. \n" ); document.write( "

Algebra.Com's Answer #695800 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
So when $\"p=0.81\"$ , the z score will correlate to an age of 21.7.
\n" ); document.write( "For $\"p=0.81\"$ , $\"z=0.8779\"$
\n" ); document.write( " $\"0.8879=%2821.7-19.4%29%2Fsigma\"$
\n" ); document.write( " $\"sigma=2.3%2F.8879\"$
\n" ); document.write( "Work that out for the answer.
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