This has been done to death, but I wrote a brief introduction to Basic Probability Distributions in R on Rpubs. One thing that that this introduction has going for it that I don’t see in many other places is that it brings together plots of each of the basic distribution functions in R along with some examples for how they are used. The hope is that the reader will get both a feel for the shapes of the probability distributions and will gain an understanding of the three standard kinds of distribution functions offered by R: the probability density, the cumulative distribution, and the quantile function. The following probability distributions are covered.
- Normal Distribution: dnorm, pnorm, and qnorm
- Poisson Distribution: dpois, ppois, and qpois
- Binomial Distribution: dbinom, pbinom, and qbinom
- Exponential Distribution: dexp, pexp, and qexp
- Chi Square Distribution: dchisq, pchisq, and qchisq
In general, R has excellent online documentation, but it can be a little dry. It can be tough to remember the differences between p-this and d-that and q-who, and I find that it helps me to remember these if I visualize the functions and work a couple of examples.
Anyway, I hope someone finds this useful!