Hi, I am trying to solve a time series problem but I am stuck with a function I am not used to work with. I have a basic yt=d +B(yt-1)+e(t) model where e(t) has mean 0 and variance sigma^2. The issue is that (e)t follows the density function that I attached to the post and it's causing me issues because of the gamma function with the (1/L) after. Does anyone know how I need to handle that part of the function to build my log likelihood function for (d,B,o^2) ? What I have tried so far has let me with the following: L=Lambda (is a known parameter), G=gamma function, o is sigma
-2/3 ln 2L - ln G(1/L) - Sum(t=2, T) (yt-d-B(yt-1))^L/(2o^2)^(1/2) - (y1-d/(1-B))^L / (2o^2/(1-B^2))^(1/2)
Is this way of handling the density function with the Gamma correct (basically ignoring it as it goes away after the derivatives)? If not could anyone shed some light on the way I should approach this to solve it?
Thanks a lot.
Log-likelihood function
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Log-likelihood function
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EViews Glenn
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Re: Log-likelihood function
There's a @gamma and @gammalog function that will do the evaluation for you.
Re: Log-likelihood function
I am not sure I understand what you mean, could you be a bit more precise? Thanks.
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EViews Glenn
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Re: Log-likelihood function
Maybe I didn't understand your question. I thought you were asking about the gamma portion of your likelihood. I was just noting that there is a function @gamma which will evaluate that portion for you.
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