# 90th percentile calculation

Question ID: 107589
 ▲ 0 ▼ ♥ 0 How is the 90th percentile calculated in the Analysis report? Marked as spam Posted by testrabbit (Questions: 144, Answers: 1) Asked on April 24, 2017 3:57 pm 77 views
 ▲ 1 ▼ ✔ Private answer The 90th percentile is the value for which 90% of the data points are smaller. The 90th percentile is a measure of statically distribution, not unlike the median. The median is the middle value. The median is the value for which 50% of the values were bigger, and 50% smaller. The 90th percentile tells you the value for which 90% of the data points are smaller and 10% are bigger. Statistically, to calculate the 90th percentile value: 1. Sort the transaction instances by their value. 2. Remove the top 10% instances. 3. The highest value left is the 90th percentile. Example: There are ten instances of transaction ''t1'' with the values 1,3,2,4,5,20,7,8,9,6 (in sec). 1. Sort by value -- 1,2,3,4,5,6,7,8,9,20. 2. Remove top 10 % -- remove the value ''20.'' 3. The highest value left is the 90th percentile -- 9 is the 90th percentile value. The 90th percentile value answers the question, ''What percentage of my transactions have a response time less than or equal to the 90th percentile value?'' Given the above information, here is how LoadRunner calculates the 90th percentile. Each value is counted in a range of values. For example, 5 can be counted in a range of 4.95 to 5.05, 7.2 in a range of 7.15 to 7.25. The 90% is taken from the range of values that the number of transaction in it and before it is >= ( 0.9 * Number of Values). Marked as spam Posted by bsmith (Questions: 0, Answers: 152) Answered on April 24, 2017 4:00 pm