> For the complete documentation index, see [llms.txt](https://docs.foretold.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.foretold.io/page-3.md).

# Probability Distributions

One of the two types of question in Foretold is the "distribution" type, made for estimating continuous distributions.

Currently a very similar distribution input method is used as with the application [Guesstimate](https://getguesstimate.com). All [Guesstimate functions](https://docs.getguesstimate.com/functions/) and distributions are supported. 

## Basic Input

The recommended way of entering most numbers is by using the basic input. Type 

```
"10 to 30"
```

In order to submit a lognormal distribution with a 5th percentile at 10 and a 95th percentile at 30. 

![](/files/-LhMClNzCyxOx2_ewt-J)

If the first number of these two is negative, then the distribution will be normal.

## Function Input

If you would like to pick a specific distribution and it's corresponding parameters, you can use the function input. If you are entering a distribution, then you will need to refer to call a specific distribution. Here are a few common ones available. A longer list is [here](https://docs.getguesstimate.com/functions/distributions.html). 

| Distribution | Use Cases                                                                         | Syntax                    |
| ------------ | --------------------------------------------------------------------------------- | ------------------------- |
| Beta         | Estimations proportions or percentages, where the answer must be between 0 and 1. | =beta(α,β)                |
| Normal       | Most uncertain things, where the uncertainty is symmetric around the median.      | =normal(μ,σ)              |
| Lognormal    | Similar to normal, but with a long tail on the right. Cannot be 0 or less.        | =lognormal(μ,σ)           |
| Uniform      | A flat distribution, where everything inside is equally likely.                   | `=uniform`(a,b)           |
| Multimodal   | Weighted combination of distributions, giving multiple peaks.                     | =mm(d1, ...,  \[w1, ...]) |