予定や経学が実際と違った場合を話してください。
"Please talk about a case where plans and plans practical and changed." I intentionally left my translation in this rather desolate state because it shows my 2 problems very well.
1) I don't really know how to convey a semantical difference between 予定 and 実際.
2) 実際 is a noun here, but 違った is a verb. Since 違った is past tense, I could imagine coaxing some noun-ish semantics into it since it kind of describes a state (in the end, past suggests that something has happened/is finished already). Nevertheless, even if both were nouns I wouldn't know how to give it a meaningful interpretation, because
(NOUN (subject) + が + complex noun-ish phrase + 場合) = very intransparent object of the full sentence