A researcher is interested in studying a new drug that is believed to significantly reduce levels of depression. However, he is concerned that the starting levels of depression are as equivalent as possible between his drug and placebo group. What can he do to better ensure equivalence here? Match on the independent variable than assign to the dependent variable, match on the dependent variable then randomly assign to groups, use a lower p-value when assessing the difference between groups, make sure the placebo control group has no history of medication treatment