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Poisson DistributIon

Hi, can anybody help me with this maths question??

Weak spots occur at random in the manufacture of wire at an average rate of 1 per 100meters. The wire is wound onto drums that carry 50meters of wire each.
a) A Company buys five drums. find the probability that exactly two of the five drums have no weak spots. (0.2241)

Reply 1

the bear

it starts off as Poisson for the weak spots on one drum... then it switches to Binomial for the five drums.

Reply 2

The Warsmith

Aww, I thought we were going to talk about the spread of fish species :frown:

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fishyyyyyyyyyyy

Original post by the bear

it starts off as Poisson for the weak spots on one drum... then it switches to Binomial for the five drums.

Do you mind show me the steps?

Reply 5

the bear

Original post by EricT

Do you mind show me the steps?

the rules of the forum are very strict about giving full working... but here are a few pointers...

a rate of 1 fault per 100m equates to ... per 50m

the chance of a drum having zero faults involves using the Poisson formula with lambda = ... and r = 0

let the answer be ???

for the second part we have fault-free drums ~ Bin( 5, ??? )

use the binomial formula with r = 2

Reply 6

the bear

Original post by Ser Alex Toyne

Aww, I thought we were going to talk about the spread of fish species :frown:

Posted from TSR Mobile

you are floundering

Reply 7

The Warsmith

No, I would say I did rather swimmingly

Careful though, or I'll batter you :wink:

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Reply 8

EricT

Original post by the bear

the rules of the forum are very strict about giving full working... But here are a few pointers...

A rate of 1 fault per 100m equates to ... Per 50m

the chance of a drum having zero faults involves using the poisson formula with lambda = ... And r = 0

let the answer be ???

For the second part we have fault-free drums ~ bin( 5, ??? )

use the binomial formula with r = 2