From the field to the data file
After conducting the experiment, we collect the data. Data is typically organized in a data file, in the so-called “long format”.
- Each experimental unit is a row in the data file.
- There are one or more columns that classify the units based on factors (treatments, blocks), and columns with a measurement (response and covariates)
- In this example, each observed yield (yij) is identified by a combination of indexes i =1…7 and j =1…4 that tag each observation with the treatment and the replication.
The data file organized in this form is the starting point for the analysis.