CREATE TABLE table_52898 ("Evaluation average  ( From February 2011 ) " FLOAT, "Evaluation average  ( From April 2009 ) " CLOB, "Evaluation average  ( Before April 2009 ) " CLOB, "% of negative evaluations" CLOB, "Submitting schedule on time" CLOB, "Punctuality/Attendance issues" CLOB, "Peak lessons taught" FLOAT)

What is the mean Evaluation number (Before April 2009) when the percentage of negative evaluations was 0.8% and the mean Evaluation number of April 2009 was 4.2?
SELECT "Evaluation average (Before April 2009)" FROM table_52898 WHERE "% of negative evaluations" = '0.8%' AND "Evaluation average (From April 2009)" = '4.2'
SELECT "Evaluation average (Before April 2009)" FROM "table_52898" WHERE "% of negative evaluations" = '0.8%' AND "Evaluation average (From April 2009)" = '4.2'