The panel shall have the sole duty to express its expert opinion as to whether or not the evidence supports the conclusion that the defendant or defendants acted or failed to act within the appropriate standards of care. After reviewing all evidence and after any examination of the panel by counsel representing either party, the panel shall, within thirty days, but no later than one hundred eighty days after the selection of the last panel member, render one or more of the following expert opinions, which shall be in writing and signed by the panelists, together with written reasons for the panel's conclusions:
La. R.S. § 37:119