Does anyone know what is the level of confidence by default? is it 80%? 90% or less?
also, can I control it somehow?
I really need to know in order to know how trustable is my test.
The level of confidence is calculated, not controllable, and there is no default value. We will suggest you make the decision once the confidence level reaches 95% or above. Generally speaking, the longer period of your test will bring more traffic and have a higher possibility of reaching a confidence level of 95% above. For more information about confidence level, please refer to the link below
Hope that helps.