Name of Test: 2-Proportion Z-Test

Formula: Calculations: = -0.0475 to 0.24783. Conclusion: We are 99% confident that the true population difference between the proportion of 12th graders who skip school and the proportion of 9th grader who skip school is between -0.0475 to 0.24783. (So, perhaps there are 4.75% more freshmen who skip than seniors or maybe it is 24.7% more ... ................
................