My teacher told me that if there are two consecutive sections like writing, math, or reading in a row then the first section will be the unscored "dummy" section.
Where the experimental section is is completely random. Not every person is going to get the same section at the same time. While taking the test you shouldn't worry about whether a section is experimental or not.
My teacher told me that if there are two consecutive sections like writing, math, or reading in a row then the first section will be the unscored "dummy" section.