Exercise: Binomial test power simulation
================

## Birth rates

Kanazawa (2007) claims that beautiful parents have more daughters

- Plan a study and calculate the sample size necessary to
  - detect a deviation from the global 106:100 male-female sex ratio
  - with about 80% power
- Wanted: Substance-matter knowledge
  - What would be a minimum relevant deviation (effect)?
  - Considering the literature on birth rates, what would be a realistic
    deviation?
- Some background
  - <https://en.wikipedia.org/wiki/Human_sex_ratio>
  - Literature cited there (e.g., Davis, Gottlieb, and Stampnitzky 1998;
    Mathews and Hamilton 2005)

### References

<div id="refs" class="references csl-bib-body hanging-indent">

<div id="ref-DavisGottlieb98" class="csl-entry">

Davis, D. L., M. B. Gottlieb, and J. R. Stampnitzky. 1998. “Reduced
Ratio of Male to Female Births in Several Industrial Countries: A
Sentinel Health Indicator?” *Journal of the American Medical
Association* 279 (13): 1018–23.
<https://doi.org/10.1001/jama.279.13.1018>.

</div>

<div id="ref-Kanazawa07" class="csl-entry">

Kanazawa, S. 2007. “Beautiful Parents Have More Daughters: A Further
Implication of the Generalized Trivers–Willard Hypothesis (gTWH).”
*Journal of Theoretical Biology* 244 (1): 133–40.
<https://doi.org/10.1016/j.jtbi.2006.07.017>.

</div>

<div id="ref-MathewsHamilton05" class="csl-entry">

Mathews, T. J., and B. E. Hamilton. 2005. “Trend Analysis of the Sex
Ratio at Birth in the United States.” *National Vital Statistics
Reports* 53 (20): 1–20.

</div>

</div>