Herbst and Marsden (2011) compared the precision, bias, and reader uncertainty of ages estimated from the scales, dorsal fin rays, and otoliths of 151 Lake Whitefish (*Coregonus clupeaformis*) captured from Lake Champlain in 2009. The initial age estimates from two readers and a consensus age between the two readers from each of the three structures (variables are the structure name with a “1” or “2” appended to denote the reader or “C” for the consensus age) are in WhitefishLC.^{1}

^{1} See “CSV file” link in “Source” section of linked page.

## Version A - Otoliths

- Use tabular, graphical, and statistical methods to describe any apparent bias in age estimates from
*otoliths*between the two readers. - Describe precision in age estimates between the two readers for
*otoliths*. - Describe any apparent bias between the
*consensus*age estimates from*otoliths*and*scales*.

## Version B - Scales

- Use tabular, graphical, and statistical methods to describe any apparent bias in age estimates from
*scales*between the two readers. - Describe precision in age estimates between the two readers for
*scales*. - Describe any apparent bias between the
*consensus*age estimates from*scales*and*fin rays*.

## Version C - Fin Rays

- Use tabular, graphical, and statistical methods to describe any apparent bias in age estimates from
*fin rays*between the two readers. - Describe precision in age estimates between the two readers for
*fin rays*. - Describe any apparent bias between the
*consensus*age estimates from*fin rays*and*otoliths*.

Solution Code:

Available upon request to students not in a class. Contact fishR maintainers.

## References

Herbst, S. J., and J. E. Marsden. 2011. Comparison of precision and bias of scale, fin ray, and otolith age estimates for Lake Whitefish (

*Coregonus**clupeaformis*) in Lake Champlain. Journal of Great Lakes Research 37:386–389.