CREATE TABLE table_60898 ("Romanised name" TEXT, "Chinese name" TEXT, "age at appointment" FLOAT, "Foreign nationality" TEXT, "Portfolio attachment" TEXT, "Govt salary" TEXT)

What is the average age at appointment of those attached to security?
SELECT AVG("age at appointment") FROM table_60898 WHERE "Portfolio attachment" = 'security'
SELECT AVG("age at appointment") FROM "table_60898" WHERE "Portfolio attachment" = 'security'