Effect size and what does it mean? Researcher has control group that received nothing, a placebo group, and an experimental group that received a new drug on depression. A depression inventory that provided a measure of depression on a 50 point scale was used (50 indicates very high). Between groups SS=1,202.313; Within groups SS=2,118.00 for total SS of 3,320.313 Drug condition for control has a mean=36.26 and n=15; placebo mean=33.33 and n=15; drug mean=24.13 and n=15