This study uses a mixed-effects modeling approach to analyze the sleepstudy dataset to investigate the effect of sleep deprivation on psychomotor performance. The repeated measurements on individual subjects are embraced in this dataset, thus being fundamentally appropriate for the use of mixed-effects models. This analysis now studies the interaction between reaction times and the length of sleep deprivation, taking into account the fixed effects and random effects. Various diagnostic evaluations indicate that model assumptions are fairly well satisfied, although minor deviations in the tails could be further examined. Results are very informative of individual-specific effects and present a thorough insight into psychomotor performance variation over time. This analysis gives adequate proof that Statistical inferences on the effects of sleep deprivation on cognition function.