Correction to: Scientific Reports https://doi.org/10.1038/s41598-017-00239-z, published online 09 March 2017

This Article contains an error in Equation 11.

\({\sigma }_{WTA}=\sqrt{\frac{1}{{\sum }_{i=1}^{N}1/{\sigma }_{i}}}\)

should read:

\({\sigma }_{WTA}=\sqrt{\frac{1}{{\sum }_{i=1}^{N}1/{\sigma }_{i}^{2}}}\)