SOLUTION: Ques-1_(The lifetime of 20,000 flashlight batteries are normally distributed,
with a mean of 370 days and a standard deviation of 30 days. How
many batteries can be expected to
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-> SOLUTION: Ques-1_(The lifetime of 20,000 flashlight batteries are normally distributed,
with a mean of 370 days and a standard deviation of 30 days. How
many batteries can be expected to
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Question 1166146: Ques-1_(The lifetime of 20,000 flashlight batteries are normally distributed,
with a mean of 370 days and a standard deviation of 30 days. How
many batteries can be expected to last less than 325 days?)
Ques-2_(The natural log of income has a normal distribution with mean 10.35
and variance 2.5. What is the probability that a person has income
below $10,000?) Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! ln 10000=9.21
so want z<(9.21-10.35)/sqrt 2.5
z<-1.14/1.58
z< -0.72
that has probability of 0.2358
the first one z=(325-370)/30 or -45/30 or -1.5
that probability is 0.0668--for some reason I had the wrong number earlier.
unrounded, multiply that by 20000 to get 1336.14 or 1336 batteries.
