Suppose we know that at a University XYZ that 15% of students receive an A in their introductory statistics class, 20% receive a B, 30% receive a C, 10% receive a D, and the rest receive an F. For comparison, a sample of 260 students at University ABC is taken and 20% received an A, 25% received a B, 25% received a C, 10% received a D, and the remaining students failed the class. When testing (at the 5% level of significance) whether the proportions between the two universities are different, what is the critical value? (please round your answer to 3 decimal places)