Question 428557
It has been observed that electrical connectors manufactured by Jolt Electrical Supply Company last an average of 18.2 months and follow a normal distribution with a standard deviation of 1.7 months. Jolt agrees to replace any connector that fails within 19 months. Out of 500 connectors sold, how many does Jolt expect to replace, on average?
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z(19) = (19-18.2)/1.7 = 0.4706
P(x< 19) = P(z< 0.4706) = 0.6810
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So 68.1% will last up to 19 mths.
So 0.3190 will fail in that period.
Jolt can expect to replace 0.319*500 = 160 units.
Cheers,
Stan H.
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