The introduction of 4G LTE communication technology was basically designed to meet the increasing demand by users for high-quality multimedia services, data communication speed and improved quality of service (QOS). It is pertinent to note that, with an ever-increasing subscriber base, it is essential to assess and analyze the network performance. To perform this task, there is a need to use the key performance indicators (KPI). This research study evaluates KPI's gathered from field measurements, using a statistical approach to establish the performance and determine the present condition of the quality of service offered by a 4G LTE network in Port Harcourt, Nigeria. In this study, a drive test approach was adopted to measure the KPI's and analysis was achieved with the use of TEMs Discovery software adopting a statistical approach. The result showed the value range of the measured KPI's were; RSSI (-90, -49.7dBm), RSRP (-117.7, -68.6 dBm), RSRQ (-14.2, -22.8dB) representing minimum and maximum values. The probability distribution of the various KPI's showed that the best signal ranges were distributed as 38.21%, 69.63% and 65.63% for RSSI, RSRP and RSRQ respectively. The KPI parameters were within the acceptable range, though require optimization to provide better service for a greater population.