Kwame is researching whether learning to knit helps to reduce anxiety in men. He recruits a sample of men (n = 28) and measures their baseline levels of anxiety, the group of men next take a knitting class and complete a knitting project over the following month. Several weeks later these men complete the anxiety measure again. If Kwame is going to test his hypothesis using a conservative two-tailed hypothesis test, what will his critical t value be? (Please omit any +/- signs for this answer.)