Average family-income gap: even vs odd-id borrowers

Sravni.ru is a financial-product aggregator. An analyst prepared a borrowers extract and wants to quickly verify the even/odd id partition is balanced — a common stratified A/B slicing trick. Table borrowers: - id INTEGER — borrower id - education education_level_t — ENUM (secondary, vocational, higher) - defaulted BOOLEAN — defaulted flag - profit_family NUMERIC(12,2) — family income in rubles On average, by how much does family income for even-id borrowers exceed that of odd-id borrowers? Return a single number rounded to two decimals; if odd-id borrowers earn more on average the result should naturally come out negative — don't wrap it in abs.