# # Probability Distributions with R

## # PDF and PMF for different distributions in R

**PMF FOR THE BINOMIAL DISTRIBUTION**

Suppose that a fair die is rolled 10 times. What is the probability of throwing exactly two sixes?

You can answer the question using the dbinom function:

```
> dbinom(2, 10, 1/6)
[1] 0.29071
```

**PMF FOR THE POISSON DISTRIBUTION**

The number of sandwhich ordered in a restaurant on a given day is known to follow a Poisson distribution with a mean of 20. What is the probability that exactly eighteen sandwhich will be ordered tomorrow?

You can answer the question with the dpois function:

```
> dpois(18, 20)
[1] 0.08439355
```

**PDF FOR THE NORMAL DISTRIBUTION**

To find the value of the pdf at x=2.5 for a normal distribution with a mean of 5 and a standard deviation of 2, use the command:

```
> dnorm(2.5, mean=5, sd=2)
[1] 0.09132454
```