A professor is trying to determine if her students guessed on a multiple choice question that had four possible answer choices. She expects that if the students guessed, the distribution of answers would be uniform for that question. She compares the observed distribution of answers with the uniform distribution. The professor conducts a chi-square Goodness-of-Fit hypothesis test at the 5% significance level.

The null and alternative hypotheses are:

H0: The student answers have the uniform distribution.
Ha: The student answers do not have the uniform distribution.
The professor calculates the test statistic is χ20=3.128.
Determine the critical value using the following portion of the χ2-table.