C: 'on average, people with more years of education are found to have higher income' refers to a positive statement rather than a normative statement.
A positive statement refers to a type of statement that establishes such hypotheses that can be empirically tested. On the other hand, a normative statement is based on subjective opinion or values. It means that positive statements can be tested, changed, or rejected by checking them against facts. And normative statements are subjective in nature that is based on opinions that cannot be tested.
The given example where it is stated that people with higher education tend to receive more income refers to a positive statement that can be tested as it is not an opinion rather it is a research-based investigation.
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