Before revision: It can be used if there are concerns that the treatment might be sensitized by the pre-test.Introduction to Research in Education by Donald Ary, Lucy Jacobs, Christine Sorensen The four groups have four different experiences: Pre-test, treatment , post-test Pre-test, no treatment, post-test Treatment , post-test No treatment, post-test .
After revision: It can be used if there are concerns that the treatment might be sensitized by the pre-test.Introduction to Research in Education by Donald Ary, Lucy Jacobs, Christine Sorensen .