A lower value indicates smaller class sizes. Andover (thick blue line) has one of the lowest values since 2006. Trend analysis indicates no significant change in ratio over time (r2=.0032). Including data for all years and ranking districts based on median student to teacher ratio (the intersection of the second quartile (green) and third quartile (purple); “whiskers” indicate top and lowest quartile data), the seven districts indicated (+) have significantly (p<= .05) higher ratios than Andover (none were significantly lower). In 2016, Andover had the lowest student to teacher ratio of any of the comparison districts.