Hi,
I am seriously sorry nick I wasn’t trying to be clever ... but I did go
through help and the manuals .. I was looking at the descriptions which does
not say that clearly..it says..
zinb estimates a maximum-likelihood zero-inflated negative binomial
regression of depvar on varlist,where depvar is a nonnegative count
variable.
Of course I didint understand the syntax diagram .. my fault.. but now I
understand that Typing [ and ] means the varlist is optional.
So the command will be zinb (var),inflate(var).. is that right?
Thanks
Rajesh
This refers to the exchange below.
The syntax diagram for -zinb-
makes it clear that independent variables
need not be specified: thus -zinb- may be
used to fit a distribution to a response
(dependent) variable alone.
So, again, do please read the help.
Nick
n.j.cox@durham.ac.uk
--------------------------- 28 February 2006
Stata offers many commands for these distributions
and others in the same territory.
Please use -help-, -search- and the manual before
sending such queries to the list.
> I have a dataset which looks like the one below
>
> Individual 1 individual 2
> Time count count
> 1 0 1
> 2 1 0
> 3 0 0
> 4 0 0
> 5 3 1
> 6 0 0
> 7 1 0
>
> Time represents months and count represents the occurance of
> an event. I
> understand that count might follow a zero inflated poisson
> distribution or
> a negative binomial distribution.
>
> Are there any stata command to check if the data fits these
> distributions?
> (just like we have the shapiro-wilk test for normality.).
>
> My objective is to see if there is any increase in the counts
> between say
> period1 (time 1 to 3) and period2 (time 4 to7) for each
> individual. And for
> all individuals taken together...
----------------------------------------------------------------------------
----
Rajesh Tharyan
> I have asked this question before but got told off... but I
> am no closer to
> finding an answer... I know there is "nbfit" to fit a
> negative binomial
> distribution to a single variable by the method of maximum
> likelihood. Is
> there something similar to fit a zero inflated negative binomial
> distribution to a single variable? I found nbvargr which fits
> a poisson and
> a negbinomial dist to a variable but nothing on zero inflated
> distributions.
>
> The only commands related to zero inflated models I found were zip and
> zinb...
>
> I am sorry if it is still a very dumb question..
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