A nurse in a cardiovascular ICU developed an intervention that she believes can reduce patient time on the ventilator post-operativelv. She recruits studyr participants from the offices of cardiovascular surgeons. She randomizes the participants to two groups, a treatment group and a control group. She provides a novel teaching intervention along with a spirometer to each participant in the treatment group one week prior to their surgery. Participants in the control group received customaryr care. After each participant's surgery, the researcher records the number of hours that they are on the ventilator post-operativelv. Which statistical test should she select to determine the effects of her intervention on time spent on ventilator post-operatively? Answers: a. Paired ttest