Dear all:
I have a question about how to interpret the interaction term in negative
binomial regression results.
Below is the section from the stata output, gender and usage are two control
variables. Dummy is a dummy variable created for 2 conditions (0 or 1).
Extraversion is considered a continuous variable (1-5), and interaction is a
product of the dummy variable and the mean-centered extraversion. I'd like
to understand the different relationships between extraversion and quantity
under condition =0 or condition =1? How can I calculate if there is a
stronger relationship between extraversion and quantity under the two
different conditions?
Quantity | Coef. Std. Err. z P>|z| [95% Conf.
Interval]
-------------+--------------------------------------------------------------
--
gender | 1.215867 .3982474 3.05 0.002 .4353161
1.996417
usage | .2103553 .1310798 1.60 0.109 -.0465563
.467267
dummy | 4.035392 .6155144 6.56 0.000 2.829006
5.241778
extraversion | 1.946443 1.131335 1.72 0.085 -.2709335
4.163819
interaction | -2.616264 1.203618 -2.17 0.030 -4.975313
-.2572159
_cons | -10.07717 4.202655 -2.40 0.016 -18.31423
-1.840122
-------------+--------------------------------------------------------------
--
I would really appreciate any assistance with this issue.
Sincerely,
Sheng Wang
The Ohio State University
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