An undergraduate psychology course only gives the grades of A, B, C, or F.

The department has determined that there should be 20% A's given, 30% B's given, 40% C's, and 10% F's given as final grades for the course. For the spring 2021 semester, 400 students took the course and 100 students received A's, 100 students received B's, 150 students received C's and 50 students received F's, so those are my observed frequencies. We want to do a Chi-square Multinomial Goodness of Fit test to see if our grading guidelines match up with what is actually happening.

The p-value for this hypothesis test is = 0.009. Make your decision to reject the null hypothesis or not, state that decision, and explain what that decision means in this specific context.