Hi all,
I am running this regression where I have the dependent variable
car(returns in percentage) and the independent variables are
mcap(marketcapitalisation), no(number of shares traded) and two dummy
variables (one for the class of director i.e executive or non executive
director and another for their type i.e male or female) and the their
interaction. The results are below
char sex[omit]m
xi: regress car mcap no i.director i.sex i.director*i.sex
car | Coef. Std. Err. t P>|t| [95% Conf.
Interval]
-------------+--------------------------------------------------------------
--
mcap | -.0031127 .000147 -21.17 0.000 -.0034009
-.0028245
no | .0030767 .0001176 26.17 0.000 .0028463
.0033072
_Idirector_2 | -.00387 .0006057 -6.39 0.000 -.0050571
-.0026829
_Isex_1 | .0004936 .0023094 0.21 0.831 -.0040328
.00502
_Idirector_2 | (dropped)
_Isex_1 | (dropped)
_IdirXsex_~1 | .0007891 .0031731 0.25 0.804 -.0054303
.0070085
_cons | .0035362 .0015175 2.33 0.020 .0005619
.0065106
I do not understand why the dummy variables are dropped (are they dropped?).
I had a read through the article on the FAQ Why do estimation commands
sometimes drop variables?. From the article I understand that stata drops
variable if there is a dependency with other IVs. Could this be because
there is a dependency between no and mcap? I do not understand how to
interpret the dependency between the dummies and other IVs.
Is there a solution to this?
Rajesh
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
