55 730
Assignments Done
97,1%
Successfully Done
In November 2017
Your physics homework can be a real challenge, and the due date can be really close — feel free to use our assistance and get the desired result.
Be sure that math assignments completed by our experts will be error-free and done according to your instructions specified in the submitted order form.
Our experts will gladly share their knowledge and help you with programming homework. Keep up with the world’s newest programming trends.

Answer on Statistics and Probability Question for Jorda Goll

Question #4252
If a shipment of 30,000 batteries is assumed to have a lifetimes which are normally distributed with mean 360 days and standard deviation 25 days what percentage could be expected to last more than 365 days?
Expert's answer
Let X be the random variable equal to the lifetime of a battery. Then by
assumption it has normal distribution with
mean 360 days and standard
deviation 25 days.
We have to find the probability P(X>365).

Notice
that the random variable Y=(X-360)/25 has normal distribution with mean 0 days
and standard deviation 1, and the
values of its probabilities is known from
tables.
Therefore
P(X>365) = P( (X-360)/25 > (365-360)/25
)
= P( Y > 5/25 )
= P(Y>0.2)
= 1 -
P(Y<0.2) =
= 1 - F^{-1}(0.2) =
= 1 - 0,5792597094
=
= 0,4207402906

Thus about 42% of all batteries, that is

& 30000 * 0.42 = 12622 batteries
have lifetime > 365 days.

Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be first!

Leave a comment

Ask Your question