Heart disease patient survival

You're a data scientist at a clinical research organization that studies heart diseases. You wonder if pericardial effusion, fluid build-up around the heart, affects heart attack patients' survival outcomes. In this exercise, you will explore how to use two statistical methods to compare survival distributions from patients with and without pericardial effusion.

The data is split up into two DataFrames:

• has_pericardial_effusion: patients with pericardial effusion
• none_pericardial_effusion: patients without pericardial effusion

The pandas package is loaded as pd and the KaplanMeierFitter class is imported from lifelines.