On a regular spring time a lot of tulip flower fields outside the Keukenhof are headed (taking the flower off) on the 30th of April or within a couple of days after it. If you want to see the flower fields as well make sure that you visit before this date!
In factorial designs, a factor is a major independent variable. In this example we have two factors: time in instruction and setting. A level is a subdivision of a factor. In this example, time in instruction has two levels and setting has two levels. Sometimes we depict a factorial design with a numbering notation.
It may use either quantitative analysis (e.g. counting the number of times that a theme occurs) and/or qualitative analysis (e.g. identifying the major themes). In either case it is important to document the criteria which are used to make decisions about rating and analyzing material.