How to find third standard deviation of a half-norm shaped distribution in python or R?

Asked Aug 22 '21 at 00:22

Active Aug 22 '21 at 14:40

Viewed 149 times

I have a data frame:

import pandas as pd
import matplotlib.pyplot as plt 

df = pd.DataFrame([100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 1, 0.9, 0.07, 0.001, 0.00001], columns=['Frequency'])

I assume this data follows a half norm distribution.

df.sort_values(by='Frequency').plot.bar(y='Frequency')
plt.savefig('test_dist.png')

This visualization results in:

How can I first fit a half-norm (half bell shape) distribution on this data and then return the third standard deviation? I could find the scipy.stats.halfnorm but don't know how to use it. I'm open to other languages such as R if you know a solution with R.

asked Aug 22 '21 at 00:22

khemedi

What is a “third standard deviation “? – IRTFM Aug 22 '21 at 00:43
Here is a question about it: https://stackoverflow.com/questions/28699342/calculate-the-3rd-standard-deviation-for-an-array – khemedi Aug 22 '21 at 00:45
I think it's ```df['Frequency'].mean() - 3 * df['Frequency'].std()``` for a normal distribution (not a half normal) – khemedi Aug 22 '21 at 00:58
Are you trying to get the third central moment? – IRTFM Aug 22 '21 at 01:06
I'm not sure what a "central moment" is. Is it like a mean? – khemedi Aug 22 '21 at 01:13

How to find third standard deviation of a half-norm shaped distribution in python or R?

0 Answers0