Customer Churn Analysis

Goal

Given a customer dataset with churn (0/1), analyze:

• Overall churn rate
• Churn by segment (plan, region)
• Numeric differences (tenure, usage)

Analysis pipeline

diagram Customer churn analysis pipeline mermaid

  flowchart LR
  A["Raw customers
(churn 0/1)"] --> B["Rate
(overall churn %)"]
  B --> C["Segment
(by plan, region)"]
  C --> D["Visualize
(churn by segment)"]
  D --> E["Model-ready
(encode, split)"]

From raw customer records to the segments most likely to leave.

Step 1: Load

Load

import pandas as pd
 
df = pd.read_csv("data/churn.csv")
print(df.shape)
print(df.head())

Step 2: Churn rate

Overall churn

rate = df["churn"].mean()
print("Churn rate:", rate)

From the book

A neat idiom that shows up throughout the book: the mean of a 0/1 column is a rate. df["churn"].mean() isn’t just an average — it’s literally “the fraction of customers who churned.” Combine it with groupby("plan")["churn"].mean() and you get a churn rate per plan with the same one-line pattern McKinney uses for group means everywhere in this chapter.

Step 3: Churn by category

Churn by segment

import seaborn as sns
import matplotlib.pyplot as plt
 
plt.figure(figsize=(7, 4))
sns.barplot(data=df, x="plan", y="churn")
plt.title("Churn rate by plan")
plt.tight_layout()
plt.show()

Step 4: Numeric differences

Tenure by churn

import seaborn as sns
import matplotlib.pyplot as plt
 
plt.figure(figsize=(7, 4))
sns.boxplot(data=df, x="churn", y="tenure")
plt.title("Tenure vs churn")
plt.tight_layout()
plt.show()

Visualize it

sketch Stayed vs churned p5.js Pause Restart

A donut chart makes the overall churn rate easy to read at a glance.

Step 5: Create a simple model-ready dataset

• Handle missing values
• Encode categories
• Split train/test

This connects back to Phase 4 preprocessing.

Deliverable

Write insights:

• Which plan/segment churns more?
• Which features differ strongly?
• What interventions might reduce churn?

🧪 Try It Yourself

Exercise 1 – Overall churn rate

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Exercise 2 – Churn rate by plan

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Exercise 3 – Compare tenure between groups

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