What is the response (Y) of interest and how is it measured? For the first research question, the length of stay is of interest. It is a continuous variable. For the second research question the outcome variable is a diagnosis of AKI, which is a nominal variable.

Are predictor variables mentioned in the problem statement? If so, how many and what are their measurement levels? Outcome (absence or presence of AKI) is in the role of predictor in the first research question. Lengthy of stay takes on the role of predictor in the second research question.

What are you being asked to deliver? A data description, an interval estimate, an answer to a question, or a predictive model? For the first research question, a test of hypothesis is appropriate to determine if statistically significant difference in length of stay exists based on the presence of AKI. For the second research question, a statistical model that describes the relationship between the likelihood of AKI and length of hospital stay will address the research question.