.. This document is auto-generated by the altair-gallery extension. Do not modify directly.

.. _gallery_error_bars_with_ci:


Error Bars showing Confidence Interval
======================================
This example shows how to show error bars using confidence intervals.
The confidence intervals are computed internally in vega by
a non-parametric `bootstrap of the mean <https://github.com/vega/vega-statistics/blob/master/src/bootstrapCI.js>`_.


.. altair-plot::
    :code-below:

    
    import altair as alt
    from vega_datasets import data

    barley = data.barley()

    points = alt.Chart(barley).mark_point(filled=True).encode(
        alt.X(
            'mean(yield)',
            scale=alt.Scale(zero=False),
            axis=alt.Axis(title='Barley Yield')
        ),
        y='variety',
        color=alt.value('black')
    )

    error_bars = alt.Chart(barley).mark_rule().encode(
        x='ci0(yield)',
        x2='ci1(yield)',
        y='variety'
    )

    points + error_bars


.. toctree::
   :hidden: