Suppose $X_{1} \sim N(10,25)$ and $X_{2} \sim N(5,4)$ in a population. You randomly select 100 samples from the population and assign treatment $A$ to half of the sample and $B$ to the rest. Simulate the sample with treatment assignments and the covariates, $X_{1}$ and $X_{2}$. Compare the distributions of $X_{1}$ and $X_{2}$ in the two treatment groups. Repeat the simulation one hundred times. Do you observe consistent results?