draw_critical_values#

pycafee.normalitycheck.shapirowilk.ShapiroWilk.draw_critical_values(self, ax=None, export=None, extension=None, file_name=None, dpi=None, decimal_separator=None)#

Draw a plot with the Shapiro Wilk critical data [1].

Parameters

axNone or matplotlib.axes.SubplotBase

If ax is None, a figure is created with a preset design. The other parameters can be used to export the graph.
If ax is a matplotlib.axes.SubplotBase, the function returns a matplotlib.axes.SubplotBase with the Shapiro Wilk critical data. In this case, the other parameters do not affect the graph.

exportbool, optional

Whether the graph should be exported (True) or not (False). The default value is None, which implies False.

file_namestr, optional

The file name. Default is None which results in a file named "shapiro_wilk_critical_plot".

extensionstr, optional

The file extension without a dot. Default is None which results in a ".png" file.

dpiint or float, optional

The figure pixel density. The default is None, which results in a 100 dpis picture. This parameter must be a number higher than zero.

decimal_separatorstr, optional

The decimal separator symbol used in the chart. It can be the dot (None or '.') or the comma (',').

Returns

axesmatplotlib.axes._subplots.AxesSubplot: The axis of the graph.

See also

get_critical_value: Returns the critical value.
fit: performs the Shapiro Wilk Normality test.

Notes

To obtain the tabulated values of the Kolmogorov Smirnov test, use:

>>> from pycafee.normalitycheck.shapirowilk import ShapiroWilk
>>> sw_test = ShapiroWilk()
>>> SW_TABLE = sw_test.SHAPIRO_WILK_TABLE
>>> print(SW_TABLE)

References

1: SHAPIRO, S. S.; WILK, M. B. An Analysis of Variance Test for Normality (Complete Samples). Biometrika, v. 52, n. 3, p. 591–611, 1965. DOI: 10.2307/2333709.

Examples

Using the figure created inside the function

>>> from pycafee.normalitycheck.shapirowilk import ShapiroWilk
>>> sw_test = ShapiroWilk()
>>> ax = sw_test.draw_critical_values(export=True)
    The 'shapiro_wilk_critical_plot.png' file has been exported

Graph showing the tabulated values of the Shapiro Wilk test for different alpha values

Using a previously created figure

>>> from pycafee.normalitycheck.shapirowilk import ShapiroWilk
>>> import matplotlib.pyplot as plt
>>> sw_test = ShapiroWilk(language='pt-br')
>>> fig, ax = plt.subplots(figsize=(8,6))
>>> ax = sw_test.draw_critical_values(ax=ax)
>>> plt.savefig("sw_plot.png")
>>> plt.show()

Graph showing the tabulated values of the Kolmogorov Smirnov test for different alpha values

get_critical_value

Gaussian