pingouin.plot_shift

pingouin.plot_shift(x, y, paired=False, n_boot=1000, percentiles=array([10, 20, 30, 40, 50, 60, 70, 80, 90]), ci=0.95, seed=None, show_median=True, violin=True)

Shift plot.

The shift plot is described in Rousselet, Pernet and Wilcox (2017).

Parameters

x, yarray_like

First and second set of observations.

pairedbool

Specify whether x and y are related (i.e. repeated measures) or independent.

New in version 0.3.0.

n_bootint

Number of bootstrap iterations. The higher, the better, the slower.

percentiles: array_like

Sequence of percentiles to compute, which must be between 0 and 100 inclusive. Default set to [10, 20, 30, 40, 50, 60, 70, 80, 90].

ci: float

Confidence level (0.95 = 95%).

seedint or None

Random seed for generating bootstrap samples, can be integer or None for no seed (default).

show_median: boolean

If True (default), show the median with black lines.

violin: boolean

If True (default), plot the density of X and Y distributions. Defaut set to True.

Returns

figmatplotlib Figure instance

Matplotlib Figure. To get the individual axes, use fig.axes.

See also

harrelldavis

Notes

Computes a shift function for two (in)dependent groups using the robust Harrell-Davis quantile estimator in conjunction with bias-corrected bootstrap confidence intervals.

References

1

Rousselet, G. A., Pernet, C. R. and Wilcox, R. R. (2017). Beyond differences in means: robust graphical methods to compare two groups in neuroscience. Eur J Neurosci, 46: 1738-1748. doi:10.1111/ejn.13610

2

https://garstats.wordpress.com/2016/07/12/shift-function/

Examples

Default shift plot

>>> import numpy as np
>>> import pingouin as pg
>>> np.random.seed(42)
>>> x = np.random.normal(5.5, 2, 50)
>>> y = np.random.normal(6, 1.5, 50)
>>> fig = pg.plot_shift(x, y)

With different options

>>> import numpy as np
>>> import pingouin as pg
>>> np.random.seed(42)
>>> x = np.random.normal(5.5, 2, 30)
>>> y = np.random.normal(6, 1.5, 30)
>>> fig = pg.plot_shift(x, y, paired=True, n_boot=2000,
...                     percentiles=[25, 50, 75],
...                     show_median=False, seed=456, violin=False)