probability distribution

Hello All,
I calculated an average latency value let say 3 units
then after observing the network I found that different nodes have the fallowing differnt latency i.e. 4, 5, 6, 7, 10 units.

now I need to assign probability to each latency considering that the value which is more closer to average latency 3 has high probability and the more far has low probability, so in this case 4 has high probability and 10 has low probability, so my question is how can I assign probabilities which should be logical and practicle.

kind regards