A professor gives a multiple choice exam where each question has five choices. The professor decides not to count a question against students if the class as a whole does significantly worse on the question than they would have done simply by guessing. In other words, the teacher tests H_0: p=0.20versus H_\text{a}: p<0.20 for each question, where p is the proportion of students who would correctly answer the question.

Suppose that 14 of 100 students correctly answer a particular question.
Assuming that the conditions for inference have been met, calculate the test statistic for the professor's significance test.