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Science Forum Index » Statistics - Math Forum » stats help needed
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| Kevin Whynot |
 Posted: Wed Jan 24, 2007 3:34 pm |
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Guest
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A delivery service has a fleet of 100 trucks. At any given time, the
probability of a truck being out of use due to factors such as breakdowns
and maintenence is 0.1.
What is the probability that from 7 to 12 trucks will be out of service at
any given time? |
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| HopefulProdigy |
| Posted: Wed Jan 24, 2007 3:34 pm |
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Guest
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Yeah, do what Kennith said...
If you have a TI-83,84, etc:
There is a function called binompdf in the distribution menu (2nd, VARS)
The way it works: binompdf(# of trials, prob. of success, # of successes)
So the probability of seven trucks breaking down:
binompdf(100,.1,7)=0.0888952464
By the way, the probability that from 7 to 12 trucks out of service is: 0.6846654972 (that includes 7 and 12 trucks being out of service.
Good luck! |
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| Stratocaster |
| Posted: Wed Jan 24, 2007 4:43 pm |
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"Kevin Whynot" <whynotk@eastlink.ca> wrote in message
news:oxOth.186820$YV4.171268@edtnps89...
Quote: A delivery service has a fleet of 100 trucks. At any given time, the
probability of a truck being out of use due to factors such as breakdowns
and maintenence is 0.1.
What is the probability that from 7 to 12 trucks will be out of service at
any given time?
I could just be making a fool of myself, but I think you could solve this
one with the binomial distribution.
Sum{k=7, 12}[ ((C_k)^100)*(p^k)*(1-p)^(100-k) ]
p= probability that a truck is out of service = .1
C- number of combinations:
i.e. ((C_k)^100) = (100!)/(k!*(100-k)!)
I could be wrong though... Does this way make sense to you? |
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| Guest |
| Posted: Wed Jan 24, 2007 7:57 pm |
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Well, you calculate the probability of exactly 7 trucks being out of
service, 8 trucks out of service, ... then add up all the probabilities.
"Kevin Whynot" <whynotk@eastlink.ca> wrote in message
news:oxOth.186820$YV4.171268@edtnps89...
Quote: A delivery service has a fleet of 100 trucks. At any given time, the
probability of a truck being out of use due to factors such as breakdowns
and maintenence is 0.1.
What is the probability that from 7 to 12 trucks will be out of service at
any given time?
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