Question: What is the income of female customers ages from 30 to 55 years old and has an occupation of machine-op-inspct?
SQL: SELECT T2.INCOME_K FROM Customers AS T1 INNER JOIN Demog AS T2 ON T1.GEOID = T2.GEOID WHERE T1.SEX = 'Female' AND T1.age >= 30 AND T1.age <= 55 AND T1.OCCUPATION = 'Machine-op-inspct'