The average transverse-momentum fraction ($\langle z \rangle$) for $\Lambda$ ($\bar{\Lambda}$) (blue) and K$^0_{\rm S}$ (red) as a function of $p_{\rm T}^{\rm S}$ in minimum bias pp collisions at $\sqrt{s}=13$ TeV. The $p_{\rm T}^{\rm S}$ ranges from 0.6 to 20 GeV/$c$. Statistical and systematic uncertainties of $\langle z \rangle$ are represented by vertical error bars and empty boxes, respectively. Data points are drawn at the corresponding average $p_{\rm T}^{\rm S}$ values in each interval. The horizontal bars represent the $p_{\rm T}^{\rm S}$ interval widths. The statistical and systematic uncertainties of the average $p_{\rm T}^{\rm S}$ values are negligible.