Chi square test Flashcards
When is this test used?
We have nominal level data
And an independent measures experimental design
How to remember what test to use?
Nick is cool
Nominal independent measures chi square
When is this test used (biology)
To find a difference in the observed frequency in data and expected frequency
How to calculated expected frequency
Calculate total of row and column and overall total
For each cell: row total x row column/overall total
Observed frequencies
For each ‘cell’ aka headcount of each group’s score Found from the experiment
Difference between observed and expected frequency
Observed frequency-expected frequency
What is done with OF and EF difference?
Square it
(Observed frequency - expected frequency) squared then what?
Divide by the EXPECTED FREQUENCY
Calculated value of Chi square
Total up the (observed frequency-expected frequency) squared /expected frequency column
Calculate degrees of freedom
(Number of rows in original data-1) x (number of columns in original data-1)
Find the critical value
At two tailed hypothesis at 0.05>p on column:
Find value at the calculated degrees of freedom
How do we know if the difference in observed and expected frequency is statistically significant?
If the calculated value is higher than the critical value so probability the difference is due to chance is less than 5%
