Chi-Square Statistics Flashcards
Data sets that are not contiguous. For example: Dead or alive, head injury or no head injury, cancer or no cancer, etc.
Categorical Variables
There is no mean,median, mode, or normal distribution for
Categorical data
Take on values that are names or labels
Categorical Variables
Different categorical variables can be associated with
-Ex: Is there a difference between college students and medical students in the number of hours of sleep per week?
Eachother
Categories may be inherent in the data or created by the researchers from
continuous data
We may want to change the data into categories if the categories are more clinically meaningful, or if the data are
Non-normally distributed
What is the conventional data presentation for the associations between categorical variables?
Contingency tables
In a contingency table, all data is independent, meaning that each person fits into only
1 box
What should we always do for contingency tables?
Put totals outside of each row/column
The appropriate statistic to use for categorical data
Chi-Square test
In the Chi-square test, we first want to establish categories and the determine the
Frequency within each category
Once we know the frequency within each category, we want to
Formulate a model
The last thing we want to do in our Chi square test is compare the normal to the expected to see if the categories are
Independent
The Chi squared test is written as
χ^2
Measure the observed frequencies and compares them to the expected
Chi-squared test