3. In a tough training program, 120 students take a series of courses. The number of
students having X failed subjects is listed in the following table.
The teacher had a theory that the probability of X = a is x = 0,1,2,3,4 with an unknown θ. After some calculation, the teacher found the
maximum likelihood estimator of θ to be 0.6. Apply an appropriate statistical test to
see whether the teacher's theory is in accordance with the observed data. Please specify