Use a query like this to have them UNchecked:
select apex_item.checkbox(1,A.ID,'CHECKED') CHECKBOX, A.*, rownum from <<table_name>> A;
By default it is not possible to exclude rows from the standard export in a report.
select apex_item.checkbox(1,A.ID,'UNCHECKED') CHECKBOX, A.*, rownum from <<table_name>> A;
in it for each row. Not sure whats going on.
<input type="checkbox" name="f01" value="8" CHECKED />
making the first column name as a checkbox type will generate a checkbox that is already checked.
select 'Y' AS <column name>, A.this, A.that from <table name> where <condition>
also generates the check boxes but as unchecked
select 'N' AS <column name>