In a city with three high schools, all the ninth graders took a standardized test, with these results: high scool mean score test number of ninth gradeglenwood 79 285central city 94 336lincoln high 72 191the city's pr manager, who never took statistics, claimed the mean score of all ninth graders in the city was 81.7 . of course, that is incorrect. what is the mean score for all ninth graders in the city? use excel. round your answer to one decimal place.