Socioeconomic inference: High-income locality composition vs. higher supermarket sales — establish the proper cause–effect classification with justification.

Given data

• I: Most citizens in the locality belong to higher income groups.
• II: The local supermarket's sales are much higher than those in other localities.

Concept/Approach

• Higher disposable income typically increases retail spending, boosting sales.

Step-by-Step reasoning
1) Higher-income composition (I) → greater purchasing power.2) Greater purchasing power → higher supermarket sales (II).

Verification/Alternative

• Reverse causality (II → I) is implausible: high sales do not convert residents into a higher-income group.

Common pitfalls

• Attributing sales differences solely to store quality without considering customer income mix.

Final Answer
Statement I is the cause and statement II is its effect.