---
title: From evidence to explanation
description: Nightingale's observations and Apollo 11 archive media, with every local resource included.
version: 0.0.1
styles: [scientific]
---

A report can place the observations beside their interpretation, an original document and a recording. Here the local media travels with the exported HTML; the external embed keeps its own availability.

## Make the evidence inspectable

```metric
value: 8.4
label: Annualized deaths per 1,000, April 1854
```

```chart
type: bar
title: Mortality varied through the first three recorded months
data:
  inline:
    - { month: Apr, rate: 8.4 }
    - { month: May, rate: 10.8 }
    - { month: Jun, rate: 7.2 }
encoding: { x: month, y: rate }
axes: { y: { label: 'Annualized deaths per 1,000' } }
```

*Source: Nightingale's mortality record, April–June 1854; each displayed annualized rate sums the causes for that month.*

```table
title: The rates behind the chart, 1854
data:
  inline:
    - { month: Apr, rate: 8.4 }
    - { month: May, rate: 10.8 }
    - { month: Jun, rate: 7.2 }
columns:
  - { key: month, label: Month }
  - { key: rate, label: 'Annualized deaths per 1,000', format: number, align: right }
```

*Source: Florence Nightingale's Crimean War mortality record, via [HistData](https://vincentarelbundock.github.io/Rdatasets/doc/HistData/Nightingale.html). The displayed rates sum preventable disease, wounds and other causes in each of the first three months. They are annualized rates, not monthly death counts. The April metric is authored from the same observations.*

```callout
kind: hold
title: Keep the unit with the number
body: An annualized rate cannot be read as the number of people who died that month. Inspect the full observations before comparing periods.
```

## The original document

```image
src: media/nightingale.jpg
alt: Florence Nightingale's 1858 diagram, with two circles of monthly mortality wedges and an explanatory legend.
caption: Florence Nightingale, Diagram of the causes of mortality in the army in the East, 1858. Public domain; David Rumsey Map Collection, via Wikimedia Commons.
```

> The Areas of the blue, red, & black wedges are each measured from the centre as the common vertex.
>
> — Florence Nightingale, the diagram's legend (1858), [original image and credits](https://commons.wikimedia.org/wiki/File:Nightingale-mortality.jpg).

## A recording gives a primary source a voice

```audio
src: media/apollo-step.mp3
title: Neil Armstrong's first words on the Moon
caption: Apollo 11, 21 July 1969 UTC. NASA Historical Sounds; public-domain mission recording.
transcript: media/transcript.md
```

```video
src: media/apollo-step.mp4
title: Beside the lunar module ladder
caption: A 12-second silent excerpt from NASA's Apollo 11 television archive. QuickTime digitization credited to Gerald Megason; public domain.
poster: media/apollo-poster.jpg
transcript: media/video-transcript.md
captions: media/captions.vtt
```

The [NASA audio collection](https://www.nasa.gov/historical-sounds/) supplies the recording; the [Apollo Lunar Surface Journal video library](https://www.nasa.gov/wp-content/uploads/static/history/alsj/a11/video11.html) supplies the film and its public-domain notice. The silent film excerpt starts 37 seconds into `a11.v1092338.mov`; its original soundtrack is omitted. Captions describe the silent scene; the audio player has its own transcript.

## An external embed

```embed
url: https://www.youtube-nocookie.com/embed/aqz-KE-bpKQ
height: 360
caption: Big Buck Bunny, Blender Foundation (2008), CC BY 3.0. The external player remains network-dependent.
```

## Guide attention across the original diagram

```scrolly
title: Read Nightingale's comparison
image:
  src: media/nightingale.jpg
  alt: Nightingale's original two-period mortality diagram.
steps:
  - title: Two periods, one unit
    text: Begin with both circles. Each compares causes of mortality through an April-to-March year.
    view: { x: 0, y: 0, zoom: 1 }
  - title: The first winter
    text: Focus on the larger right-hand diagram. Its blue area records deaths from preventable disease; the printed legend explains that the wedges encode area.
    view: { x: 0.35, y: 0.05, zoom: 1.6 }
    highlight: { x: 0.55, y: 0.1, w: 0.4, h: 0.7 }
```

## A formula needs its assumptions

For an independent Bernoulli sample, the estimated standard error of a sample proportion is

$$
\operatorname{SE}(\hat p) = \sqrt{\frac{\hat p(1-\hat p)}{n}}
$$

Here $n$ is the sample size and $\hat p$ the observed proportion. It is an estimate under a sampling model, not a formula for Nightingale's annualized rates.