[en] The charge ratio (μ⁺/μ^-) of cosmic ray muons at sea level was calculated basically using the scaling hypothesis and the recent ISR experimental data on inclusive reactions p+p → i+X (i=p,n,π^+-,K^+-). Special attention is paid to the primary nucleus-air nucleus collision. The observed scaling property and collective behaviour in nucleus-nucleus collisions were taken into consideration. It is found that for the μ⁺/μ^- ratio the inclusion of nucleus-nucleus collisions results in a better agreement with experimental data in comparison with the values derived from the usual superposition models. The muon spectrum at sea level is also presented. (author)