document.write( "Question 1174438: The mean lifetime of a printer is 48 months, with a standard deviation of 7 months. If the distribution of the printer lifetime is normal, for how many months should a guarantee be made if the manufacturer does not want to exchange more than 10% of the watches? Assume the variable is normally distributed. (Round up whatever you get for the number of months the guarantee should be given for.) \n" ); document.write( "

Algebra.Com's Answer #799853 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi\r\n" );
document.write( "  Normal Distribution:  μ = 48m  and   σ = 7mos \r\n" );
document.write( "manufacturer does not want to exchange more than 10% of the watches\r\n" );
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document.write( "  z = 1.282 represents 10% of the Standard Normal Curve\r\n" );
document.write( "  \r\n" );
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document.write( "    x = 7(1.282) + 48 = 56.97 (rounding down to 56)  \r\n" );
document.write( "90% are expected to have lifetime of 56mo\r\n" );
document.write( " For how many months should a guarantee be made:  56mo\r\n" );
document.write( "Wish You the Best in your Studies.\r\n" );
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