# XWUIChartErrorBand

An error-band chart: a fixed-type (`errorBand`) wrapper around `XWUIChart` that draws each
series as a line with a shaded band around it, conveying the uncertainty or variability
surrounding the central trend. Pass `series` of `{ name, data: [{ x, y }] }` plus an optional
`block` preset (1-4) and `size` (`sm` / `md` / `lg`); the shared block config also
exposes legend, grid, axis, data-label, and line-style toggles. Use it when each point carries a
margin of error you want shown as a continuous envelope rather than discrete bars.

## Basic Usage

Two named series of monthly values rendered as lines with surrounding error bands at the medium
size preset.

```example
file: examples/BasicUsage.ts
html: examples/BasicUsage.html
title: Basic Usage
description: Two monthly series drawn as central lines wrapped in shaded uncertainty bands.
```

## Temperature Forecast with Uncertainty

A 7-day outlook where the central forecast line is bracketed by lower and upper bounds that widen
toward the end of the week as confidence drops.

```example
file: examples/TemperatureForecast.ts
html: examples/TemperatureForecast.html
title: Temperature Forecast with Uncertainty
description: Forecast line with lower/upper bands that widen across the 7-day horizon, in °C.
```

## A/B Test Conversion ± CI

A variant's weekly conversion estimate shown with its 95% confidence band, which tightens as more
samples accumulate.

```example
file: examples/AbTestConversion.ts
html: examples/AbTestConversion.html
title: A/B Test Conversion ± CI
description: Weekly conversion estimate wrapped in a narrowing 95% confidence band, in %.
```

```api
```