The Decision
Kaiser Permanente is considering the adoption of a treatment method called a clinical pathway. A clinical pathway provides specific steps to follow in treating a given condition, based on
medically accepted best practices. When no clinical pathway is used, each doctor treats a given condition according to his or her training, experience and best judgment.

To decide whether the clinical pathway improves outcomes, the hospital has undertaken a clinical trial. Patients needing knee replacement surgery were randomly assigned to two groups. One group’s
treatment followed a clinical pathway, the other group’s did not. Two outcome measures were taken. The first was the average length of stay in the hospital. Shorter hospital stays are associated
with improved outcomes for patients. The second outcome measure is called a FIM score. FIM stands for “functional integrity measure,” and is a scale running from 0 to 100 that measures the state
of health of the whole person. A score of 0 means the person is dead; a scale of 100 means the person is in extremely good physical condition. Taken together, the measures help the hospital
determine whether use of the clinical pathway improves patient well-being.

Data
The results of the clinical trial are found in a dataset entitled pathway.xlsx. This can be found on the course website in the Case Studies module. The data set contains four variables:
1. LOSNON: the length of the hospital stay in days for a non-pathway patient
2. FIMNON: the functional integrity measure for a non-pathway patient
3. LOSPATH: the length of the hospital stay in days for a pathway patient
4. FIMPATH: the functional integrity measure for a pathway patient.

Statistical Analysis
The goal of the statistical analysis is to determine the effect of the clinical pathway on two patient outcomes: length of stay (LOS) and the functional integrity measure (FIM). This involves
comparing the levels and the variability of outcomes of pathway and non-pathway patients. Please do so by answering the following questions.

1. Create a table of descriptive statistics that summarizes the mean, median, standard deviation, minimum and maximum for each of the four variables (see case study 1 for example of
formatting).
2. Create 95% confidence intervals for the mean length of stay of the clinical pathway group and the mean length of stay of the non-pathway group. Do they overlap?
3. Calculate and interpret a 95% confidence interval for the difference in the mean length of stay of pathway and non-pathway patients.
4. Create 95% confidence intervals for the mean FIM score of the pathway group and for the mean FIM score of the non-pathway group. Do they overlap?
5. Calculate and interpret a 95% confidence interval for the difference in the mean FIM score of pathway and non-pathway patients.