Last school year, the student body of a local university consisted of 30% freshmen, 24% sophomores, 26% juniors, and 20% seniors. A sample of 300 students taken from this year's student body showed the following number of students in each classification: freshmen 83, sophomores 68, juniors 85, and seniors 64. The school superintendent is interested in determine whether there has been a significant change in the classification between last school year and this school year.

Deteremine the correct null hypothesis for this problem