Contingency Tables with pd.crosstab() in Pandas

Question

Given customer survey records with `device_type` and `churn_status`, compute a normalized percentage cross-tabulation table showing churn rates by device.

Accepted Answer

Optimal Solution:
import pandas as pd

# normalize='index' computes percentages across rows (row totals = 1.0)
ctab = pd.crosstab(
    df['device_type'],
    df['churn_status'],
    normalize='index'
)

Technical Explanation:
`pd.crosstab()` calculates contingency frequency tables. `normalize='index'` computes conditional relative frequencies along each row.

device_type	churn_status
iOS	Retained
iOS	Churned
Android	Retained

device_type	Churned	Retained
Android	0	1
iOS	0.5	0.5