Refresh some basic logical propositions (or statements):
implication: if P then Q (P—>Q)
inverse: if not P then not Q (-P—>-Q)
converse: if Q then P (Q—>P)
contrapositive: if not Q then not P (-Q—>-P)
contradition: if P then not Q (P—>-Q)
Mathematically or logically speaking, if the implication statement holds, then the contrapositive holds, but the inverse does not hold, i.e., if P then Q, then we can get if not Q then not P, but we can not get if not P then not Q.
Mr. Jones, if you get a grade below 70 on the final, you are going to flunk this course.
We adapt it in a logical implication form:
Mr. Jones, if P then Q, where
P: you get a grade below 70 on the final
Q: you are going to flunk this course
Considering the context, we can also get that the inverse holds: if you get a grade above er or equal to 70, then you are going to pass this course(if not P then not Q ).
Question: when do statistical programming, what types of logics you use?
Answer: Not all mathematically. see
if score<70 then grade="flunk"; ***_if P then Q_**;
else grade=“pass”; *if not P then not Q;