I wanted to ask how do I make inference (confidence intervals, hypothesis testing, etc...) on the the standard deviation or variance, when my distribution is non-normal ?

In particular, I have two cases: A right-skewed distribution and a bimodal distribution that seems to come from two normal distributions.

To my understanding, in both cases inference on the mean is easy, since my sample is large (approx. 60-70 cases). But what about the standard deviation ?

Thanks !