Question: How are differences in a person's income or wealth included when calculating QALYs? Group of answer choices The calculation of a QALY uses the proportional difference in income as an adjustment to the QALY. The calculation of a QALY uses four income quartiles for adjusting the QALY. The calculation of a QALY is based on ten income categories to adjust each person's QALY. The calculation of a QALY is the same regardless of a person's income or wealth.