[currysoup_t]

What leads you to believe performance follows a normal distribution?

For a given especially slow request would you expect a corresponding especially fast request?

[DenisM]

Standard deviation applies to all distributions, not just the normal distribution.

[teej]

You are arguing against yourself here. Having the mean and 95th/99th percentile is going to give you a better picture of the distribution than mean alone. Mean alone actually doesn’t give you ANY idea of the distribution. I don’t know why OP is being downvoted, managing to 95th percentile is very common practice and I also thought was a missing addition to the article.