According to Gejdoš (2006), the improvement of processes is amongst the basic attributes of the Six Sigma
method. The aim of the process improvement is the performance at the level 6σ. It is an enabled process, in which
out of the million opportunities for a mistake, i.e. not fulfilling the customer's specification, it happens only 3.4
times. Process capability - the sigma level is an indicator of the quality of the process, therefore the likelihood of
errors in the process. The higher the sigma, the lower the probability that the process will produce an error.