# fourfold: Fourfold Table

Exercise template for computing joint probabilities from a 2x2 table based on three randomly-drawn conditional or marginal probabilities.

**Name:**

`fourfold`

**Type:**

**Related:**

**Description:**

Computing all four joint probabilities (in percent) in a fourfold table based on two randomly-generated conditional probabilities and one marginal probability. The exercise is a cloze with four numeric answers presented in a list.

**Solution feedback:**

Yes

**Randomization:**

Random numbers

**Mathematical notation:**

Yes

**Verbatim R input/output:**

No

**Images:**

No

**Other supplements:**

No

*(Note that the HTML output contains mathematical equations in MathML. It is displayed by browsers with MathML support like Firefox or Safari - but not Chrome.)*

**Demo code:**

```
library("exams")
set.seed(1090)
exams2html("fourfold.Rnw")
set.seed(1090)
exams2pdf("fourfold.Rnw")
set.seed(1090)
exams2html("fourfold.Rmd")
set.seed(1090)
exams2pdf("fourfold.Rmd")
```