Handle missing values and check target class balance

Analyze the dataset for missing values and check the distribution of the income target variable. Write 3 to 4 points on how the missing data should be handled and the potential impact of the class distribution on tree splitting.

Start by locating the dataset and notebook entry point, then inspect missing values and the distribution of the income target variable. Document 3 to 4 points covering missing-data handling and how class distribution may affect tree splitting; done means the analysis and recommendations are written in the notebook or project documentation.

Written by the indexing model from the issue text.