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Archived Comments for: Platelet-rich plasma (PRP): an adjuvant to hasten hamstring muscle recovery. A randomized controlled trial protocol (ISCRTN66528592)

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  1. Sample size calculation faulty?

    Reinhard Vonthein, Universitat zu Lubeck

    17 October 2014

    Inserting the numbers given into the formula provided gives an alternative mean time to return to play close to zero. What is the rationale for that assumption?

    Quoted RTP times are obviously from a positively skewed distribution and may be censored at 16 weeks. Together with the small sample sizes these facts speak against planing a t-test as implied by the formula.


    Competing interests

    None declared