Percentile shows the value below which a given percentage of observations fall. This helps understand variations in measurements. For instance, 50th percentile (p50) shows median response time, while p95 shows what 95% of users experience.
Due to peaks, average response time can be skewed upwards. A few slow responses can dramatically affect the average. Always analyze percentiles (p50, p90, p95, p99) alongside averages for a complete picture.