We investigate the correlations between radio pulse nulling fraction (NF) and emission height based on simulation of 9000 nulling pulsar samples each with 1000 rotations. Each pulsar is randomly assigned an obliquity and a viewing angle. Visible emission is determined in a geometry, in which the emission is tangential to the local magnetic field lines and aligned with the line of sight. In an emission region with multiple emission segments, a detectable null occurs when a favorable condition is present to trigger switching in plasma density to zero in all the visible segments. The resulting NF distribution is consistent with the latest observations. We find that pulsars with low NFs and large obliquity angles tend to emit from higher heights, and vice versa. We demonstrate that variation in the NF is large among pulsars with low emission heights. However, the variation decreases and the NFs tend to be low for pulsars with emission at higher heights. We show that the NF exhibits varying correlation with the rotation period. Our results indicate that younger pulsars tend to null at higher emission heights than older pulsars. This suggests weakening of the radio emission mechanism with height as a pulsar ages.