# freq: List current frequency information. In riskyr: Rendering Risk Literacy more Transparent

## Description

`freq` is a list of named numeric variables containing 11 frequencies:

## Usage

 `1` ```freq ```

## Format

An object of class `list` of length 11.

## Details

1. the population size `N`

2. the number of cases for which `cond.true`

3. the number of cases for which `cond.false`

4. the number of cases for which `dec.pos`

5. the number of cases for which `dec.neg`

6. the number of cases for which `dec.cor`

7. the number of cases for which `dec.err`

8. the number of true positives, or hits `hi`

9. the number of false negatives, or misses `mi`

10. the number of false positives, or false alarms `fa`

11. the number of true negatives, or correct rejections `cr`

These frequencies are computed from basic parameters (contained in `num`) and computed by using `comp_freq`.

The list `freq` is the frequency counterpart to the list containing probability information `prob`.

Natural frequencies are always expressed in relation to the current population of size `N`.

Key relationships:

1. to probabilities: A population of `N` individuals can be split into 2 subsets in 2 different ways:

1. by condition: The frequency `cond.true` depends on the prevalence `prev` and the frequency `cond.false` depends on the prevalence's complement `(1 - prev)`.

2. by decision: The frequency `dec.pos` depends on the proportion of positive decisions `ppod` and the frequency `dec.neg` depends on the proportion of negative decisions `(1 - ppod)`.

The population size `N` is a free parameter (independent of the essential probabilities `prev`, `sens`, and `spec`).

If `N` is unknown, a suitable minimum value can be computed by `comp_min_N`.

2. to other frequencies: In a population of size `N` the following relationships hold:

• `N = cond.true + cond.false` (by condition)

• `N = dec.pos + dec.neg` (by decision)

• `N = dec.cor + dec.err` (by correspondence of decision to condition)

• `N = hi + mi + fa + cr` (by condition x decision)

Visualizations of the current frequency information are provided by `plot_tree` and `plot_mosaic`.

`comp_freq` computes current frequency information; `num` contains basic numeric variables; `init_num` initializes basic numeric variables; `prob` contains current probability information; `num` contains basic numeric parameters; `init_num` initializes basic numeric parameters; `txt` contains current text information; `init_txt` initializes text information; `pal` contains current color information; `init_pal` initializes color information.
Other lists containing current scenario information: `accu`, `num`, `pal`, `prob`, `txt`
 ```1 2 3``` ```freq <- comp_freq() # => initialize freq to default parameters freq # => show current values length(freq) # => 11 ```