Researchers conducted a study where $300$ high school students were randomly assigned to one of two groups: Group A used a new interactive learning method, and Group B used the traditional method. After a semester, $70$ percent of students in Group A achieved a passing grade, while $60$ percent of students in Group B achieved a passing grade. Based on these results, which of the following statements must be true?

I. The new interactive learning method is definitively more effective than the traditional method for all high school students.
II. If this study were replicated with another $300$ randomly selected high school students, exactly $70$ percent of Group A and $60$ percent of Group B would achieve passing grades.
III. The observed difference in passing rates between Group A and Group B is solely due to the difference in teaching methods.