Probability Density Functions

[Jeunemaitre]

It depends on what you're using them for. There's a good site specific to log and weibull distributions and properties/characteristics of the pdf curves, but it's not very general (they have an online reference section that you can go through page by page for a quick education on pdf relationships with survival/reliability curves, but not much for other probability applications). The main site is www.weibull.com, and the section on life data analysis with weibull and log distributions is http://www.weibull.comfedatawebcontents.htm.

I've only been using these things professionally and don't know all the math behind them so I may be off base in interpreting you're interest. If you're really in it for academic understanding, I'm not sure these will be that great a help.

Good luck though...