Chi-square goodness-of-fit test

Mr. Rigor, a math teacher at a large university, has a reputation for being a harsh grader, but has he earned that reputation? A reporter for the student newspaper selects a random sample of $60$ of Mr. Rigor’s recent students and asks them what grade they earned in his class. The reporter plans to perform a chi-square goodness-of-fit test at the $\alpha=0.01$ level to determine if the distribution of grades in Mr. Rigor’s classes differs from the grade distribution for all math classes at the university. The data and the school-wide distribution of math grades is given below. Grade | A | B | C | D/F - | :-: | :-: | :-: | :-: School-wide distribution of math grades| $20\%$ | $40\%$ | $30\%$ | $10\%$ Observed distribution for Mr. Rigor's students | $9$ | $16$ | $25$ | $10$ **Which of the following is a correct null hypothesis for this test?** [[☃ radio 1]]