D. Cristol et al. published results of their studies of two subspecies of dark-eyed juncos in the paper "Migratory Dark-Eyed Juncos, Junco hyemalis, Have Better Spatial Memory and Denser Hippocampal Neurons Than Nonmigratory Conspecifics" (Animal Behaviour, Vol. 66, Issue 2, pp. 317-328).
One of the subspecies migrates each year, and the other does not migrate. A hypothesis test is to be performed to decide whether the mean wing lengths for the two subspecies (migratory and nonmigratory) are different.
a. Identify the variable.
b. Identify the two populations.
c. Determine the null and alternative hypotheses.
d. Classify the hypothesis test as two tailed, left tailed, or right tailed.