The χ2 value, also known as the chi-square value, is a statistical measure used in a chi-square test to determine if there is a significant relationship between two categorical variables. It quantifies the difference between the observed and expected frequencies.
Imagine you are playing a game of darts with your friend. You both throw darts at a dartboard and after each round, you calculate how far off your throws were from the bullseye. The χ2 value in a chi-square test is like measuring the total distance between your throws and the bullseye - it tells you how far off your observed data is from what you would expect if there was no relationship between the variables.
Degrees of Freedom: Represents the number of categories that can vary freely in a statistical analysis. In the context of chi-square tests, it refers to the number of categories minus 1.
Significance Level: The level at which we decide whether to reject or fail to reject the null hypothesis. Commonly denoted as α (alpha), it is typically set at 0.05.
Expected Frequencies: The frequencies that would be expected under the assumption that there is no association between two categorical variables being analyzed using a chi-square test. These values are calculated based on proportions or probabilities from theoretical distributions or previous data.
Study guides for the entire semester
200k practice questions
Glossary of 50k key terms - memorize important vocab
© 2024 Fiveable Inc. All rights reserved.
AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.