Transcript What is the Chi-square test for?

Two Variable Statistics
Introduction To
Chi-Square Test for Independence
Correlation
Finding the relationship between two
quantitative variables without being
able to infer causal relationships
Correlation is a statistical technique
used to determine the degree to which
two variables are related
What is the Chi-square test for?

The chi-squared or Χ2 test is used to
determine whether two variables from
the same sample are independent or
not independent.

A chi-squared test is designed to
analyze categorical data. That
means that the data has been
counted and divided into categories.
Appropriate Categorical Data
For example, if you want to test whether
attending class influences how students perform
on an exam, using test scores (from 0-100) as
data would NOT be appropriate for a Chi-square
test.
However, arranging students into the categories
"Pass" and "Fail" would be appropriate.
More Important facts about Chi-Squared
Test
The chi-squared test is only meant to test the
probability of independence of a distribution of
data. It will NOT tell you any details about the
relationship between them.
The variables you consider must be mutually
exclusive; participation in one category should
not entail or allow participation in another. In
other words, the data from all of your cells should
add up to the total count, and no item should be
counted twice.
How do you calculate the chisquared test by hand?