Question

Functionally important traits in animals tend to vary little from one individual to the next within populations, possibly because individuals who deviate too much from the mean have lower fitness. If this is the case, does variance in a trait rise after it becomes less functionally important? Billet et al. (2012) investigated this question with the semicircular canals (SC) of the three-toed sloth (Bradypus variegatus). The authors proposed that since sloths don't move their heads much, the functional importance of SC is reduced, and may vary more than it does in more active animals. They obtained the following measurements of the ratio of the length to width of the anterior SC in 6 sloths. Assume this represents a random sample. In other, more active animals, the standard deviation of this ratio is 0.09.

Sloth CW Ratios

1.53

1.06

0.93

1.38

1.47

1.2

Fill in the blank for a with the estimate of the standard deviation of this measurement in three-toed sloths to two decimals, and include the leading zero ___________________

The 95% confidence interval for the standard deviation of this data is __________ < ? < ______________ (two decimals - include the leading zero)

Does this interval include the value obtained from other species? (answer yes or no in blank d) _________________

Answer 1