Some suggestions

[chengeaa]

I think if I am to understand these correctly, there are a few things that could perhaps do with some minor tweaks:

• Under variability, it might be of some use to note that this is a sample and not a population standard deviation
• For discrete distributions, it is more accurate to refer to P(X=x) as their PMF, rather than PDF
• I believe the power law distribution is typically thought of as a continuous, not discrete distribution