document.write( "Question 378308: Quick Start Company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a Quick Start battery is normally distributed, with a mean of 44.0 months and a standard deviation of 8.3 months.
\n" ); document.write( "(a) If Quick Start guarantees a full refund on any battery that fails within the 36-month period after purchase, what percentage of its batteries will the company expect to replace? \r
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\n" ); document.write( "\n" ); document.write( "(b) If Quick Start does not want to make refunds for more than 15% of its batteries under the full-refund guarantee policy, for how long should the company guarantee the batteries?
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Algebra.Com's Answer #268802 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!


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document.write( "Hi
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document.write( "*Note: 
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document.write( " = -8/8.3 = -.9639 
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document.write( "P(z <-.9639) = .1675  Expect to replace 16.75%\r
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document.write( "P(z = -1.0364) = .15
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document.write( "-1.0364 = (x - 44)/8.3
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document.write( "8.3*(-1.0364) + 44 = x
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document.write( "-8.6021 + 44 = 35 months\r
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