Question

In order to improve the English speaking and reasing skills of their students, Jack Box Elementary assigns students whose native language is Spanish to a bilingual program for 8 week. To test the effectiveness of this program, then also need a control condition, in which the children are exposed to 8 weeks of English-only instruction. Students are assigned randomly to one condition or the other. Should this variable "Intevention Type" be manipulated within-participants or between?