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Glen_b
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With regard to the following:

  • the mean of a Binomial dist is n*p$np$

  • the variance is np(1-p)$np(1-p)$

  • the mean of a Poisson dist is lambda$\lambda$, which we can imagine as n*p$n\times p$

  • the variance of a Poisson is the same as the mean

Now, if a Poisson is the limit to a Binomial with parameters n$n$ and p$p$, such that n$n$ increases to infinity and p$p$ decreases to zero while their product remains constant, then assuming that n$n$ and p$p$ are not converged to their respective limits, the expression np is always greater than np*(1-p)$np$ is always greater than $np(1-p)$, therefore the variance of Binomial is less than that of Poisson. That would imply that Binomthe Binomial is below in the tails and above elsewhere.

With regard to the following:

  • the mean of a Binomial dist is n*p

  • the variance is np(1-p)

  • the mean of a Poisson dist is lambda, which we can imagine as n*p

  • the variance is the same

Now, if a Poisson is the limit to a Binomial with parameters n and p, such that n increases to infinity and p decreases to zero while their product remains constant, then assuming that n and p are not converged to their respective limits, the expression np is always greater than np*(1-p), therefore the variance of Binomial is less than that of Poisson. That would imply that Binom is below in the tails and above elsewhere.

With regard to the following:

  • the mean of a Binomial dist is $np$

  • the variance is $np(1-p)$

  • the mean of a Poisson dist is $\lambda$, which we can imagine as $n\times p$

  • the variance of a Poisson is the same as the mean

Now, if a Poisson is the limit to a Binomial with parameters $n$ and $p$, such that $n$ increases to infinity and $p$ decreases to zero while their product remains constant, then assuming that $n$ and $p$ are not converged to their respective limits, the expression $np$ is always greater than $np(1-p)$, therefore the variance of Binomial is less than that of Poisson. That would imply that the Binomial is below in the tails and above elsewhere.

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Germaniawerks
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With regard to the following:

  • the mean of a Binomial dist is n*p

  • the variance is np(1-p)

  • the mean of a Poisson dist is lambda, which we can imagine as n*p

  • the variance is the same

Now, if a Poisson is the limit to a Binomial with parameters n and p, such that n increases to infinity and p decreases to zero while their product remains constant, then assuming that n and p are not converged to their respective limits, the expression np is always greater than np*(1-p), therefore the variance of Binomial is less than that of Poisson. That would imply that Binom is below in the tails and above elsewhere.