title: How to calculate sample size and why.
abstract: Calculating the sample size is essential to reduce the cost of a study and to prove the hypothesis effectively.
  Referring to pilot studies and previous research studies, we can choose a proper hypothesis and simplify the studies by using a website or Microsoft Excel sheet that contains formulas for calculating sample size in the beginning stage of the study.
  There are numerous formulas for calculating the sample size for complicated statistics and studies, but most studies can use basic calculating methods for sample size calculation.
authors.affiliation: Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea. kjhnav@naver.com
authors.forename: Jeehyoung
authors.initials: J
authors.lastname: Kim
authors.forename: Bong Soo
authors.initials: BS
authors.lastname: Seo
mesh_terms: D016009:Chi-Square Distribution; D012107:Research Design; D018401:Sample Size; D013223:Statistics as Topic / Q000379:methods*
keywords: Sample size