SOLUTION: Many electronic devices use disposable batteries, which eventually have to be replaced. Assume that for one particular brand and type of battery, the distribution of the hours of u
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Question 1161929: Many electronic devices use disposable batteries, which eventually have to be replaced. Assume that for one particular brand and type of battery, the distribution of the hours of useful power can be approximated well by a Normal model. The mean is 140 hours, and the stand deviation is 4 hours.
The marketing department wants to write a guarantee for battery life. What lifespan should they quote so that they can expect 98% of the batteries to meet the guarantee? Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! want the 2nd percentile.
Can do with 2nd VARS 3 invnorm (0.02,140,4)<131.781 hours or 131.8 hours. The most conservative approach with rounding would be down to 131 hours.
Look at the upper 98th percentile, since that is what is wanted. That means the cutoff is at the 2nd percentile.
