How is the "Average Response time" calculated?

tmx040#sh stati slb all
Real service r_075_08888 8888 UP ACTIVE
        Main health check: 8888 tcp UP
        Max Conn Count:            1000
        Current Connection Count: 0
        Outstanding Request Count: 0
        Total Hits:                0
        Total Bytes In:            0
        Total Bytes Out:           0
        Total Packets In:          0
        Total Packets Out:         0
        Average Response time:     0.010 ms
     The response time measurement depends on the type of the real service.
For HTTP/HTTPS real services, the response time is measured as the time
difference from the last byte of HTTP request sent to the first byte of
valid HTTP response received. For TCP/TCPS real services the response
time is the time difference between a TCP SYN packets sent to the TCP
connection established on the Array. This method is not precise to the time
value base on the formula and instantaneous time in milli-sec of the statistic.

"Average Response Time" is calculated based on two types of response time:
1. Health check response time
   (1)RS with main health check:
       The repsonse time of main health check will be used.
   (2)RS without main health check, but with additional health checks:
       The repsonse time of first additional health check will be used.
   (3)RS without main health check, and without additional health checks too:
       No response of health check can be used.

2. Real traffic response time(only on http|https real service)

"Average Response Time" is the average value of last 20 response times.