Performance output - what is the +/- value?

Hello,

I have a quick question to which I couldn't find the answer by searching the other threads or the information available on the RapidMiner website. I'm not from a data science background but have been using RapidMiner for some classification using a few different machine learning processes. I have used cross validation and an example of the performance results is this (a very poor classifier for my data):

Precision: 95.06% +/- 6.06% (micro average: 94.76%) (positive class: true)

                                    True false         True true         Class precision

Pred. false                   3915                 587                  86.96%

Pred. true                    12                      217                  94.76%

class recall                  99.69%              26.99%       

I'm not concerned with the actual performance of the model but more the value I've bolded. What does this +/- range represent? I had originally thought it was a range of precision but the positive value is above 100%. Is this due to the class distribution difference?

Thank you in advance!