<p>This work is concerned with studying the event-by-event pseudo-rapidity fluctuations in relativistic heavy-ion collisions in terms of <i>φ</i> measure (this measure of event-by-event fluctuations), its multiplicity, and target dependence. The study was conducted using ⁸⁴Kr projectile for the heavy (AgBr) and light (CNO) groups of targets present in the nuclear emulsion. Based on the quantity of shower particles, three overlapping multiplicity classes have been created from the total number of events. The <i>φ</i> values are found to be more than zero for each multiplicity class, suggesting the presence of significant correlation in the multiparticle generation at relativistic energy. The <i>φ</i> values for the AgBr target are found to be higher than those for the CNO target. This finding suggests that heavier projectiles have a higher association.</p>