`scipy.stats._stats_py:relfreq`

source: build-install/usr/lib/python3.14/site-packages/scipy/stats/_stats_py.py:2440

Signature

def relfreq(a, numbins = 10, defaultreallimits = None, weights = None)

Summary

Return a relative frequency histogram, using the histogram function.

Extended Summary

A relative frequency histogram is a mapping of the number of observations in each of the bins relative to the total of observations.

Parameters

a : array_like: Input array.
numbins : int, optional: The number of bins to use for the histogram. Default is 10.
defaultreallimits : tuple (lower, upper), optional: The lower and upper values for the range of the histogram. If no value is given, a range slightly larger than the range of the values in a is used. Specifically (a.min() - s, a.max() + s), where s = (1/2)(a.max() - a.min()) / (numbins - 1).
weights : array_like, optional: The weights for each value in a. Default is None, which gives each value a weight of 1.0

Returns

frequency : ndarray: Binned values of relative frequency.
lowerlimit : float: Lower real limit.
binsize : float: Width of each bin.
extrapoints : int: Extra points.

Examples

import numpy as np
import matplotlib.pyplot as plt
from scipy import stats
rng = np.random.default_rng()
a = np.array([2, 4, 1, 2, 3, 2])
res = stats.relfreq(a, numbins=4)

✓

res.frequency
np.sum(res.frequency)  # relative frequencies should add up to 1

✗

np.float64(0.9999999999999999)

Create a normal distribution with 1000 random values

samples = stats.norm.rvs(size=1000, random_state=rng)

✓

Calculate relative frequencies

res = stats.relfreq(samples, numbins=25)

✓

Calculate space of values for x

x = res.lowerlimit + np.linspace(0, res.binsize*res.frequency.size,
                                 res.frequency.size)

✓

Plot relative frequency histogram

fig = plt.figure(figsize=(5, 4))
ax = fig.add_subplot(1, 1, 1)

✓

ax.bar(x, res.frequency, width=res.binsize)
ax.set_title('Relative frequency histogram')
ax.set_xlim([x.min(), x.max()])

✗

(-3.7730786689688216, 3.0004074615798233)

plt.show()

✓