document.write( "Question 1010455: The life expectancy of a typical lightbulb is normally distributed with a mean of 1,975 hours and a standard deviation of 25 hours. What is the probability that a lightbulb will last between 1,950 and 2,050 hours?
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\n" ); document.write( " 0.84
\n" ); document.write( " 0.77
\n" ); document.write( " 0.82
\n" ); document.write( " 0.89
\n" ); document.write( " Please show how you got the answer so I can learn please.
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Algebra.Com's Answer #626855 by stanbon(75887) $\"\"$ $\"About$

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The life expectancy of a typical lightbulb is normally distributed with a mean of 1,975 hours and a standard deviation of 25 hours. What is the probability that a lightbulb will last between 1,950 and 2,050 hours?
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\n" ); document.write( "z(1950) = (1950-1975)/25 = -1
\n" ); document.write( "z(2050) = (2050-1975)/25 = 75/25 = 3
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\n" ); document.write( "P(1950< x <2050) = P(-1< z <3) = 0.84
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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\n" ); document.write( "\n" ); document.write( "0.84
\n" ); document.write( "0.77
\n" ); document.write( "0.82
\n" ); document.write( "0.89 \n" ); document.write( "

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