Of the 258 patients admitted during the time frame of the study, the researchers selected 120 from a list of previously designated surgical patients. This is an example of what type of sampling method?

Let’s look at the use of ANOVA in the following nursing research article:
Özden, D., & Görgülü, R. S. (2015). Effects of open and closed suction systems on the haemodynamic parameters in cardiac surgery patients. Nursing in Critical Care, 20(3), 118–125. doi:10.1111/nicc.12094