I have two samples of the same size, one being the 'treated' group, and the other used as a 'control' group.
Each group have a different univariate variable (stress level), repeatedly observed over 100 periods.
Suppose that after period 75 the traetment begins.
I want to test the significance of the hipothesis that the treatment has an impact in the stress level in the individuals within the 'treated' group.
Is there a statistical test that checks signifficant differences accross groups and accross time?