Studying the influence of metabolic differences among individuals on survival or reproductive success in nature requires that an individual’s metabolism doesn’t vary too much from time point to time point. To investigate, Hayes and O’Connor (1999) measured repeatability of thermogenic capacity (ability to generate heat) by recording maximal rate of oxygen consumption (VO₂max) in high-altitude deer mice exposed to cold temperatures in a wind tunnel. A sample of 34 mice were measured twice about 68 days apart. The two measurements on each mouse, in ml/min, are given below.

a. Calculate the variance components of VO₂max within and among deer mice.

b. What is the repeatability of thermogenic capacity, as measured using VO₂max under cold exposure?

c. What are your assumptions in parts (a) and (b)?