Question
In: Statistics and Probability
The number of hours a battery lasts before failing follows an exponential distribution with a mean...
The number of hours a battery lasts before failing follows an exponential distribution with a mean of μ = 24.5 hours and a standard deviation of 10 hours. Eric buys a pack of 64 batteries. Find the probability that the average number of hours a battery lasts is 21 hours or less.
a. 0.0026
b. 0.9974
c. 0.3632
d. -2.80
Solve the problem and show all your work below. Draw appropriate pictures!
Solutions
Expert Solution
Solution :
Given that,
mean = 
= 24.5
standard deviation = 
= 10
n = 64
= 24.5
= /
n = 10/
64=1.25
P(
<21 ) = P[(
-
) /
< (21-24.5) /1.25 ]
= P(z <-2.8 )
Using z table
= 0.0026
probability= 0.0026
orchestra answered 2 years agoRelated Solutions
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