A study factor is a single biological or technical parameter that you control, for example, genotype, diet, environmental stimulus, age, column length, spray voltage, or collision energy. Normally, you track only the parameters that differentiate samples from each other.
When you choose the type of study factor, consider one of the following:
- Categorical study factors are used for general sample names. Categorical study factors sort alphanumerically.
- See Add categorical study factors.
- Numeric study factors are used for time points, sample injection amounts, and so on. Numeric study factors sort numerically.
- See Add numerical study factors.
- Biological study factors are used when one of the following are true:
- There are both technical and biological replicates in a run.
- The study has a nested or paired design. - Biological study factors are sorted alphanumerically. See Add biological replicate study factors.
NOTE
Biological study factors are used rarely.
For additional information, see Technical and biological replicates.