Two researchers, Wiebe and Bortolotti, in 2002 examined the color in tail feathers of Northern Flickers. It sometimes occurs that these birds have one tail feather, which differed from the rest in terms of its color. This was perhaps because the feather had re-grown after having been lost. The "odd" feather and a "typical" feather from each of the selected birds were analyzed with respect to the degree of "yellowness." Larger values of the measurement indicate the feather color is less yellow. The question they wished to address was whether or not "odd" feathers and the "typical" feathers differed with respect to the yellowness of their color.

What is the value of the test statistic?

Answer is t= 2.04 but need an explanation of how to get it.