CREATE TABLE table_2571 ("Sigma level" FLOAT, "Sigma  ( with 1.5\\u03c3 shift ) " TEXT, "DPMO" TEXT, "Percent defective" TEXT, "Percentage yield" TEXT, "Short-term C pk" TEXT, "Long-term C pk" TEXT)

What is the percentage yield for a DPMO of 3.4?
SELECT "Percentage yield" FROM table_2571 WHERE "DPMO" = '3.4'
SELECT "Percentage yield" FROM "table_2571" WHERE "DPMO" = '3.4'