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Erratum to: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters

  • The original article was published in BMC Medical Research Methodology 2011 11:102

Erratum

After publication of the original article [1], it came to the authors’ attention that there was a typing error in equation 16. There should be a rho on the denominator of this equation.

The published version of equation 16 is:

$$ m=\frac{\left(1-\rho \right){n}_{I\ }}{k-{n}_I\left(c{v}^2+1\right)} $$

The correct version of equation 16 is:

$$ m=\frac{\left(1-\rho \right){n}_{I\ }}{k-{n}_I\left(c{v}^2+1\right)\rho } $$

References

  1. 1.

    Hemming K, Girling AJ, Sitch AJ, Marsh J, Lilford RJ. Sample size calculations for cluster randomised controlled trials with a fixed number of clusters. BMC Med Res Methodol. 2011;11:102. doi:10.1186/1471-2288-11-102.

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Correspondence to Karla Hemming.

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The online version of the original article can be found under doi:10.1186/1471-2288-11-102.

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Hemming, K., Girling, A.J., Sitch, A.J. et al. Erratum to: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters. BMC Med Res Methodol 17, 8 (2017). https://doi.org/10.1186/s12874-017-0292-x

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