I wanted to test if there is a difference in the proportion of the number of students who have a score higher than the average mean scale score for the subject of Mathematics for schools having outlets with lead > 15 ppb. I decided to use the Chi square test of proportions for this.
H0 : There is no difference in the proportion of the economic backgrounds(ie economically disadvantaged and NOT economically disadvantaged) of the schools having > 15 ppb lead water levels with mean scale score greater than the average mean scale score of all such schools.
H1 : There is a difference in the proportion of the economic backgrounds of the schools having > 15 ppb high lead water levels with mean scale score greater than the average mean scale score of all such schools.
Significance level : alpha = 0.05