R help - Dec 2007 - logistic regression using "glm",which "y" is set to be "1"

Dear friends :
    using the "glm" function and setting family=binomial, I got a list
of
coefficients.
The coefficients reflect the effects  of predicted variables on the
probability of the response to be "1".
My response variable consists of  "A" and "D" . I don't
know which level of
the response was set to be 1.
is the first element of the response set to be 1?
   Thank all in advance.
   Regards,

-----
Best regards,
Bin Yue

*************
student for a Master program in South Botanical Garden , CAS

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On Wed, 2007-12-05 at 18:06 -0800, Bin Yue wrote:
> Dear friends :
>     using the "glm" function and setting family=binomial, I got a
list of
> coefficients.
> The coefficients reflect the effects  of predicted variables on the
> probability of the response to be "1".
> My response variable consists of  "A" and "D" . I
don't know which level of
> the response was set to be 1.
> is the first element of the response set to be 1?
>    Thank all in advance.
>    Regards,
> 
> -----
> Best regards,
> Bin Yue

As per the Details section of ?glm:

For binomial and quasibinomial families the response can also be
specified as a factor (when the first level denotes failure and all
others success) ...


So use:

  levels(response.variable)

and that will give you the factor levels, where the first level is 0 and
the second level is 1. 

If you work in a typical English based locale with default alpha based
level ordering, it will likely be A (Alive?) is 0 and D (Dead?) is 1.

HTH,

Marc Schwartz