Statistics question: a binomial model can be approximated with what other model?

Asked by 717richboy (234) November 14th, 2012

I’m not the best when it comes to stats, and I am confused about which model closely resembles the binomial model. Thanks in advance.

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Normal distribution?

Well, we’re really not supposed to give away homework answers on Fluther, but I do know this one. I’m trying to think how to lead you to it without just telling you.

When you have very large samples sizes, there is a type of distribution that begins to behave similarly to a binomial distribution. There are some formulas: for large n, μ ≈ np and σ ≈ √(np(1-p)).

Got any ideas now?

Mariah (22837)

I want to say normal distribution, but I’m still not 100% sure.

717richboy (234)

Normal model*

717richboy (234)

Right, so how can you be more confident in that answer? Look at my formulas. These are the formulas for approximating a binomial distribution: μ ≈ np and σ ≈ √(np(1-p)). n and p are variables you see in binomial distributions, right? So the approximation must use μ and σ. Which distribution do you know that uses those variables? You’re right – in the normal distribution mu is the mean and sigma is the standard deviation.

Mariah (22837)
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AHA! Thank you so much, makes perfect sense now! You should be my Stats teacher! :-P

717richboy (234)

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