- Check the conditions for Fisher’s Exact Test
- Explain the relationship of two qualitative binary variables using Fisher’s Exact Test
Fisher’s Exact Test
Fisher’s Exact Test (also known as Fisher’s Exact Test of Independence) is a statistical significance test used in the analysis of a [latex]2 \times 2[/latex] contingency table.
It is used to determine whether or not there is a significant association between two categorical variables.
Let’s revisit the motorcycle example.
A 2004 study titled “Motorcycle rider conspicuity and crash related injury: case-control study” looked at a similar context and, based on the conclusions of that study[1], the researcher decides to combine cells from the table below into a two-way table.
| Black helmet | White helmet | Red helmet | Yellow/orange helmet | |
| No injury | 8 | 4 | 3 | 2 |
| Injured or killed | 20 | 2 | 1 | 1 |
[Trouble viewing? Click to open in a new tab.]
- Independence/Randomness Condition: The sample from our population should be independent, random sample or independent sample that can be considered representative of the population.
- Large Sample Sizes Condition: The sample sizes need to be large enough so that the expected count in each cell is at least five.
- Wells, S., Mullin, B., Norton, R., Langley, J., Connor, J., Lay-Yee, R., & Jackson, R. (2004, April 10). Motorcycle rider conspicuity and crash related injury: case-control study. BMJ (Clinical research ed.), 328(7444), 857. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC387473/ ↵