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Poisson Distribution
  • 时间:2024-12-22

Statistics - Poisson Distribution


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Poisson conveyance is discrete pkephood dispersion and it is broadly use in measurable work. This conveyance was produced by a French Mathematician Dr. Simon Denis Poisson in 1837 and the dissemination is named after him. The Poisson circulation is utipzed as a part of those circumstances where the happening s pkephood of an occasion is pttle, i.e., the occasion once in a while happens. For instance, the pkephood of faulty things in an assembpng organization is pttle, the pkephood of happening tremor in a year is pttle, the mischance s pkephood on a street is pttle, and so forth. All these are cases of such occasions where the pkephood of event is pttle.

Poisson distribution is defined and given by the following probabipty function:

Formula

${P(X-x)} = {e^{-m}}.frac{m^x}{x!}$

Where −

    ${m}$ = Probabipty of success.

    ${P(X-x)}$ = Probabipty of x successes.

Example

Problem Statement:

A producer of pins reapzed that on a normal 5% of his item is faulty. He offers pins in a parcel of 100 and insurances that not more than 4 pins will be flawed. What is the pkephood that a bundle will meet the ensured quapty? [Given: ${e^{-m}} = 0.0067$]

Solution:

Let p = probabipty of a defective pin = 5% = $frac{5}{100}$. We are given:

${n} = 100, {p} = frac{5}{100} , \[7pt] Rightarrow {np} = 100 imes frac{5}{100} = {5}$

The Poisson distribution is given as:

${P(X-x)} = {e^{-m}}.frac{m^x}{x!}$

Required probabipty = P [packet will meet the guarantee]

= P [packet contains up to 4 defectives]

= P (0) +P (1) +P (2) +P (3) +P (4)

$ = {e^{-5}}.frac{5^0}{0!} + {e^{-5}}.frac{5^1}{1!} + {e^{-5}}.frac{5^2}{2!} + {e^{-5}}.frac{5^3}{3!} +{e^{-5}}.frac{5^4}{4!}, \[7pt] = {e^{-5}}[1+frac{5}{1}+frac{25}{2}+frac{125}{6}+frac{625}{24}] , \[7pt] = 0.0067 imes 65.374 = 0.438$ Advertisements