Medicine and Clinical Studies Managers at Cedarcrest Hospital in Newington, Connecticut, are interested in the length of stay (in days) of patients admitted for open-heart surgery. Hospital managers have decided to limit their investigation to open-heart patients who were operated on within the last year. Thirty open-heart surgery patients admitted to the hospital within the last year are selected. What is the population of interest, the sample, and the variable in this problem? Write a Solution Trail for this problem.