Pearson χ² (2 cél.)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Pearson χ² (2 cells) calculator is a useful tool for statisticians and researchers who need to calculate the Pearson χ² statistic in samples with 2 categories.
This calculator calculates the Pearson χ² statistic based on the formula: Σ(O-E)²/E, where O is the observation, E is the expectancy and Σ is the sum.
The Pearson χ² is widely used to test the independence between two categorical variables. It is also used to calculate the probability that the observations are independent.
Important considerations: ensure that the observations are independent and that the categories are mutually exclusive.
Frequently asked questions
What is the Pearson χ² formula?
The Pearson χ² formula is Σ(O-E)²/E, where O is the observation, E is the expectancy and Σ is the sum.
When to use the Pearson χ² calculator?
Use the Pearson χ² calculator to test the independence between two categorical variables or to calculate the probability that the observations are independent.
What is the expectancy (E) in the Pearson χ² formula?
The expectancy (E) is the expected probability of an observation, based on the distribution of the data.
Can I use the Pearson χ² calculator with samples smaller than 2?
No, the Pearson χ² calculator is designed for samples with 2 categories. For samples smaller than 2, you need to use a different calculator or method.
What are the important considerations when using the Pearson χ² calculator?
Ensure that the observations are independent and that the categories are mutually exclusive.