The rating of each test shall be completed and the resulting list established not later than thirty days after the date on which the test was held, unless such time is extended by the Director of Personnel for reasons which he shall record in the official records of his office. Each person competing in any test shall be given written notice of his final earned rating and of his relative standing on the list, or of his failure to attain a place on the list. Each person competing in a test shall, in accordance with regulations adopted by the Director of Personnel be entitled to inspect his ratings and test papers. A manifest error in rating a test shall be corrected if called to the attention of the Director of Personnel within one month after the establishment of the list, but such correction shall not invalidate any appointment previously made from such a list.