In a city with three high schools, all the ninth graders took a Standardized Test, with these results: High School Mean Test Score Number of ninth graders (Frequency) Glenwood 82 280 Central Lincoln 92 73 316 167 The city's PR manager, who never took statistics, claimed the mean score of all ninth graders in the city was the average of 82, 92, and 73, which is 82.3. Of course, that is incorrect. What is the mean score for all ninth graders in the city? Round to one decimal place. Mean of all ninth grader's scores = 85.6