A new treatment for depression involves a one month stay on a Caribbean island and daily therapy sessions with a team of 8 professionals. A researcher knows that people with untreated depression miss an average of μ = 4.30 days of work per month (σ = 1.1). It was found that a random sample of 121 depressed individuals who underwent the new treatment missed an average of M = 4.08 days of work per month following treatment. Thus, the research question is: what is the impact of this treatment on absenteeism (i. e., days missed from work)?