TY - JOUR T1 - Sample size and power estimation for studies with health related quality of life outcomes: a comparison of four methods using the SF-36. JO - Health Qual Life Outcomes UR - http://eprints.whiterose.ac.uk/22/ PY - 2004/05/25 AU - Walters SJ ED - DO - DOI: 10.1186/1477-7525-2-26 VL - 2 SP - 26 Y2 - 2024/12/26 ER -