An ecological researcher studied the interaction between birds of two subspecies, the Carolina Junco and the Northern Junco. He placed a Carolina male and a Northern male, matched by size, together in an aviary and observed their behavior for 45 minutes beginning at dawn. This was repeated on different days with different pairs of birds. The table shows counts of the episodes in which one bird displayed dominance over the other-for instance, by chasing it or displacing it from its perch.18 Consider a sign test, using a non directional alternative, to compare the subspecies.

(a) What is the value of the test statistic?
(b) The P-value for the sign test is 0.008. If α = 0.01, what is your conclusion?

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Number of episodes in which Northern was dominant Carolina was dominant Pair 4 16 17 2 24 40