Understanding the basics of Beta Distribution

What is the Beta Distribution?

Sarowar Ahmed
2 min readJun 18, 2024

Imagine you’re a chef experimenting with a new recipe. You want to create a sauce that strikes the perfect balance between sweetness and tanginess. The Beta Distribution allows you to model the distribution of probabilities over a continuous interval, making it ideal for scenarios where outcomes are bounded and diverse.

The probability density function (PDF) of the Beta Distribution

Where:
▪ x represents the value of the random variable between 0 and 1.
▪ a and b are shape parameters that control the shape of the distribution.
▪ B(α,β) is the Beta function, ensuring that the area under the curve equals 1.

Examples of the Beta Distribution

Conversion Rates:
▪ In digital marketing, you want to optimize the conversion rate of your website. The Beta Distribution can help you model the distribution of conversion rates across different user segments, allowing you to identify the most effective strategies.

Quality Control:
▪ A manufacturing company wants to ensure that the proportion of defective products remains within acceptable limits. The Beta Distribution can model the distribution of defect rates, aiding in setting quality control thresholds.

Visualization

Scenario

Suppose a company wants to estimate the proportion of its customers who are satisfied with their service. Based on previous surveys, the company believes the satisfaction rate follows a Beta distribution with shape parameters α = 4 and β = 6. We want to find the probability that more than 50% of customers are satisfied.

Solutions

Let’s calculate this using Python

import scipy.stats as stats

# Parameters
alpha = 4
beta = 6
x = 0.5 # threshold we are interested in

# Calculate the CDF for x = 0.5
cdf_value = stats.beta.cdf(x, alpha, beta)

# Calculate the probability that X > 0.5
probability = 1 - cdf_value
probability

Executing this code will give us the probability that more than 50% of customers are satisfied.

Why Does This Matter?

The Beta Distribution is incredibly versatile and finds applications in fields such as statistics, machine learning, and Bayesian inference. It allows us to model uncertainties and make informed decisions in diverse contexts.

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Sarowar Ahmed

An IIT Madras Scholar | LinkedIn Top Statistics Voice | Researching on Quantitative Finance | Data Science | AI | Machine Learning | Deep Learning |