Tips for troublesome sample-size calculation

Korean Journal of Anesthesiology 2020; 73(2):114-120

https://doi.org/10.4097/kja.19497

 

The article by In J, et al. entitled, “Tips for troublesome sample-size calculation.” contained an error in the Equation 12.

 

Before correction:

$$\mathrm{Adjusted} \mathrm{sample} \mathrm{size}=\frac{Calculated\mathit{ }sample\mathit{ }size}{1-dropout\mathit{ }rate}=\frac{39}{1-0.9}=43.33$$ (12)

 

The correct information is found below:

$$\mathrm{Adjusted} \mathrm{sample} \mathrm{size}=\frac{Calculated\mathit{ }sample\mathit{ }size}{1-dropout\mathit{ }rate}=\frac{39}{1-0.1}=43.33$$ (12)

 

The value for dropout rate was incorrectly printed as 0.9. The value for dropout rate should be corrected to 0.1.

The authors apologize for any inconvenience this mistake may have caused.