An introduction to power and sample size estimation.

@article{Jones2003AnIT,
  title={An introduction to power and sample size estimation.},
  author={Stephen R. Jones and Stephen Carley and Magnus Harrison},
  journal={Emergency medicine journal : EMJ},
  year={2003},
  volume={20 5},
  pages={453-8}
}
The importance of power and sample size estimation for study design and analysis.