Teachers at a large high school have become concerned that increasing class sizes hinder their ability to deliver quality instruction and consequently have a negative impact on student's grades.
To investigate, a committee of teachers selected a random sample of classes offered at the high school during the previous school year. For each class, they recorded the number of students in the class and the final average grade for students in the class (expressed as a percent). To reduce variability, they only selected classes considered to be at the "standard" level . No honors/advanced classes were included in their sample and no remedial/low level classes were included in their sample. A scatterplot of the data is shown below.
Based upon the scatterplot, what can the committee conclude?