The correct validation rule formula to ensure that the Scheduled Ship Date field is properly filled out before setting the Opportunity to Closed Won is:
OR(ISPICKVAL( StageName ,"Closed Won") && ( Scheduled_Ship_Date_cCloseDate)>14,ISBLANK(Scheduled_Ship_Date_c)) This formula checks two conditions: if the StageName is Closed Won and the Scheduled Ship Date is more than 14 days after the Close Date, or if the Scheduled Ship Date is blank. If either condition is true, the validation rule will fire and prevent saving the record. The other formulas are incorrect because they either use incorrect syntax (such as "=" instead of "," or missing parentheses) or incorrect logic (such as checking if the Scheduled Ship Date is less than 14 days after the Close Date)