The school board of each school district, at some time prior to the school district election each year, may appoint 4 inspectors of election as additional election officers to act with the clerk, moderator and school board. If the number of voters qualified to vote at an election shall exceed 2,000, the school board may appoint for such election 2 additional inspectors for each additional 2,000 qualified voters or fraction thereof. If the number of voters qualified to vote at any school district election shall exceed 4,000, the school board may appoint such additional inspectors as they may deem necessary for the efficient conduct of the election, so long as the total number of election officials shall not exceed 24. The inspectors shall be qualified voters at said election. They shall assist the school district moderator in counting votes for school district officers and questions.