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

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.

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.

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.