Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.
Aprenda P-value Interpretation | Statistical Analysis of A/B
Quizzes & Challenges
Quizzes
Challenges
/
Applied Hypothesis Testing & A/B Testing

bookP-value Interpretation

Understanding p-values is crucial for interpreting the results of A/B tests. A p-value is a statistical measure that helps you determine whether the observed difference between your control and treatment groups is likely due to chance or represents a real effect.

What Does a P-value Represent?

In A/B testing, the p-value quantifies the probability of obtaining results as extreme as those observed, assuming that the null hypothesis (no difference between groups) is true.

  • A p-value does not tell you the probability that the null hypothesis is true;
  • Instead, it tells you how likely it is to observe your data, or something more extreme, if the null hypothesis were actually true.

For example, a p-value of 0.03 means there is a 3% probability of observing your results, or something more extreme, purely by random chance under the null hypothesis. This does not mean there is a 3% chance the null hypothesis is correct.

Interpreting Small and Large P-values

  • A small p-value (typically less than 0.05) suggests the observed effect is unlikely to be due to random variation alone. This leads you to reject the null hypothesis in favor of the alternative;
  • The 0.05 threshold is arbitrary, and a p-value just below 0.05 does not necessarily indicate a strong effect;
  • A large p-value does not prove there is no effect; it simply means the data do not provide strong evidence against the null hypothesis.

Common Misinterpretations

  • A p-value does not indicate the probability that the results will replicate;
  • It does not measure the size or importance of the effect;
  • The p-value is solely a measure of evidence against the null hypothesis, not a direct measure of practical significance or effect size.
Note
Definition

Statistical significance occurs when a test result is unlikely to have happened by chance, as measured by the p-value. If the p-value falls below a predetermined threshold (commonly 0.05), the result is considered statistically significant, suggesting that the observed effect is probably real and not just due to random variation.

question mark

Which statement best describes the meaning of a p-value in the context of an A/B test?

Select the correct answer

Tudo estava claro?

Como podemos melhorá-lo?

Obrigado pelo seu feedback!

Seção 5. Capítulo 6

Pergunte à IA

expand

Pergunte à IA

ChatGPT

Pergunte o que quiser ou experimente uma das perguntas sugeridas para iniciar nosso bate-papo

Suggested prompts:

Can you explain what the null hypothesis is in more detail?

How should I choose the right p-value threshold for my experiment?

What are some alternatives to using p-values in A/B testing?

Awesome!

Completion rate improved to 3.23

bookP-value Interpretation

Deslize para mostrar o menu

Understanding p-values is crucial for interpreting the results of A/B tests. A p-value is a statistical measure that helps you determine whether the observed difference between your control and treatment groups is likely due to chance or represents a real effect.

What Does a P-value Represent?

In A/B testing, the p-value quantifies the probability of obtaining results as extreme as those observed, assuming that the null hypothesis (no difference between groups) is true.

  • A p-value does not tell you the probability that the null hypothesis is true;
  • Instead, it tells you how likely it is to observe your data, or something more extreme, if the null hypothesis were actually true.

For example, a p-value of 0.03 means there is a 3% probability of observing your results, or something more extreme, purely by random chance under the null hypothesis. This does not mean there is a 3% chance the null hypothesis is correct.

Interpreting Small and Large P-values

  • A small p-value (typically less than 0.05) suggests the observed effect is unlikely to be due to random variation alone. This leads you to reject the null hypothesis in favor of the alternative;
  • The 0.05 threshold is arbitrary, and a p-value just below 0.05 does not necessarily indicate a strong effect;
  • A large p-value does not prove there is no effect; it simply means the data do not provide strong evidence against the null hypothesis.

Common Misinterpretations

  • A p-value does not indicate the probability that the results will replicate;
  • It does not measure the size or importance of the effect;
  • The p-value is solely a measure of evidence against the null hypothesis, not a direct measure of practical significance or effect size.
Note
Definition

Statistical significance occurs when a test result is unlikely to have happened by chance, as measured by the p-value. If the p-value falls below a predetermined threshold (commonly 0.05), the result is considered statistically significant, suggesting that the observed effect is probably real and not just due to random variation.

question mark

Which statement best describes the meaning of a p-value in the context of an A/B test?

Select the correct answer

Tudo estava claro?

Como podemos melhorá-lo?

Obrigado pelo seu feedback!

Seção 5. Capítulo 6
some-alt