Hi!
I'm new on Stata and I apologize in advance for trivial questions
I'm working on a mixed models analysis.

Given the example command:
"mixed edd preg age||id:"
edd is a measure of heart dimensions
preg is number of pregnancies
age is age of patients
I wonder when is necessary to use "c.age" or/and "c.preg" in the command to specify I'm using a continuous variable. I've seen this change significantly my results.

Thank you in advance!
Isotta