Crossbill Finches Have Beaks That Overlap with the Top Beak

question 30

Multiple Choice

Crossbill finches have beaks that overlap with the top beak to one side or the other of the lower beak. Most populations have 50:50 ratios of "right-handed" and "left-handed" beaks, and the handedness of the beaks is thought to be randomly determined, so we expect to see equal numbers of right-beak and left-beak finches. Consider a survey of 140 crossbill finches, which reveals 84 with right beaks and 56 with left beaks. What is the conclusion of a two-sided binomial test using the normal distribution to approximate the binomial?

• A) Fail to reject null hypothesis, we lack evidence that the handedness of the beaks is non-random.
• B) Fail to reject null hypothesis, we have evidence that the handedness of the beaks is non-random.
• C) Reject null hypothesis, we lack evidence that the handedness of the beaks is non-random.
• D) Reject null hypothesis, we have evidence that the handedness of the beaks is non-random.

---

Definitions:

Kyphosis

A forward rounding of the back, leading to a hunched posture, which can be due to various medical conditions.

External Auditory Meatus

The ear canal, a pathway running from the outer ear to the middle ear.

Temporal Bone

The temporal bone is a large bone at the side and base of the skull, which houses the structures of the ear.

Paget's Disease

A long-term skeletal disorder characterized by the enlargement and deformity of bones resulting from irregular bone loss and regeneration.