If you do intend on working with only in-memory PL/SQL type-based tables, this is what you need to do:
CREATE OR REPLACE PROCEDURE ProcedureX
TYPE AVERAGE_COUNT_TBL IS TABLE OF NUMBER;
CURSOR C IS SELECT 10 FROM DUAL;
FETCH C BULK COLLECT INTO AVERAGE_COUNT;
The cursor is just used to demonstrate.
I'll add that your question is poor, as you didn't even take the time to make sure that
AVERAGE_COUNT_TBL matched with itself on the next row - you used
AVG_TRANS_HOUR_TBL instead. If you expect random internet people to spend time writing quality answers, would it hurt to make sure your question was of sufficient quality?