Tossing a coin

In the video, you have seen our custom get_heads_prob() function that estimates the probability of success of a binomial distribution. In this exercise, you will use it yourself and verify whether it does its job well in a coin-flipping experiment.

Watch out for the confusion: there are two different probability distributions involved! One is the binomial, which we use to model the coin-flipping. It's a discrete distribution with two possible values (heads or tails) parametrized with the probability of success (tossing heads). The Bayesian estimate of this parameter is another, continuous probability distribution. We don't know what kind of distribution it is, but we can estimate it with get_heads_prob() and visualize it.

numpy and seaborn have been imported for you as np and sns, respectively.

Cet exercice fait partie du cours

Bayesian Data Analysis in Python

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Instructions

Generate a list of 1000 coin tosses (0s and 1s) with 50% chance of tossing heads, and assign to the variable tosses.
Use the tosses and the get_heads_prob() function to estimate the heads probability, and assign the result to heads_prob.
Draw a density plot of the distribution of the heads probability you have just estimated.

Exercice interactif pratique

Essayez cet exercice en complétant cet exemple de code.

# Generate 1000 coin tosses
tosses = ____(____, ____, ____)

# Estimate the heads probability
heads_prob = ____

# Plot the distribution of heads probability
____(____, shade=True, label="heads probabilty")
plt.show()

Modifier et exécuter le code

Cet exercice fait partie du cours

Bayesian Data Analysis in Python

IntermédiaireNiveau de compétence

4.8+

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Take your first steps in the Bayesian world. In this chapter, you’ll be introduced to the basic concepts of probability and statistical distributions, as well as to the famous Bayes' Theorem, the cornerstone of Bayesian methods. Finally, you’ll build your first Bayesian model to draw conclusions from randomized coin tosses.

Exercise 1: Who is Bayes? What is Bayes?Exercise 2: Bayesians vs. Frequentists Exercise 3: Probability distributions Exercise 4: Probability and Bayes' Theorem Exercise 5: Let's play cards Exercise 6: Bayesian spam filter Exercise 7: What does the test say?Exercise 8: Tasting the Bayes Exercise 9: Tossing a coin

Exercice en cours

Exercise 10: The more you toss, the more you learn Exercise 11: Hey, is this coin fair?

It’s time to look under the Bayesian hood. You’ll learn how to apply Bayes' Theorem to drug-effectiveness data to estimate the parameters of probability distributions using the grid approximation technique, and update these estimates as new data become available. Next, you’ll learn how to incorporate prior knowledge into the model before finally practicing the important skill of reporting results to a non-technical audience.

Exercise 1: Under the Bayesian hood Exercise 2: Towards grid approximation Exercise 3: Grid approximation without prior knowledge Exercise 4: Updating posterior belief Exercise 5: Prior belief Exercise 6: The truth of the prior Exercise 7: Picking the right prior Exercise 8: Simulating posterior draws Exercise 9: Reporting Bayesian results Exercise 10: Point estimates Exercise 11: Highest Posterior Density credible intervals Exercise 12: The meaning of credibility

Apply your newly acquired Bayesian data analysis skills to solve real-world business challenges. You’ll work with online sales marketing data to conduct A/B tests, decision analysis, and forecasting with linear regression models.

Exercise 1: A/B testing Exercise 2: Simulate beta posterior Exercise 3: Posterior click rates Exercise 4: A or B, and how sure are we?Exercise 5: How bad can it be?Exercise 6: Decision analysis Exercise 7: Decision analysis: cost Exercise 8: Decision analysis: profit Exercise 9: Regression and forecasting Exercise 10: Defining a Bayesian regression model Exercise 11: Analyzing regression parameters Exercise 12: Predictive distribution

In this final chapter, you’ll take advantage of the powerful PyMC3 package to easily fit Bayesian regression models, conduct sanity checks on a model's convergence, select between competing models, and generate predictions for new data. To wrap up, you’ll apply what you’ve learned to find the optimal price for avocados in a Bayesian data analysis case study. Good luck!

Exercise 1: Markov Chain Monte Carlo and model fitting Exercise 2: Markov Chain Monte Carlo Exercise 3: Sampling posterior draws Exercise 4: Interpreting results and comparing models Exercise 5: Inspecting posterior draws Exercise 6: Comparing models with WAIC Exercise 7: Making predictions Exercise 8: Sample from predictive density Exercise 9: Estimating test error Exercise 10: How much is an avocado?Exercise 11: Fitting the model Exercise 12: Inspecting the model Exercise 13: Optimizing the price Exercise 14: Final remarks