Bayes Theorem

Do we learn Bayes Theorem in A level Probability for H2 Maths?

I've just been taught that P(X|Y) = [P(X ⋂ Y)]/[P(Y)] in Statistics and this appeared rather different from the one I've encountered on the internet, which is given by P(X|Y) = {[P(Y|X)] [P(X)]}/[P(Y)]. Please kindly advise, thanks.

Student X

They are equivalent.

{[P(Y|X)] [P(X)]}/[P(Y)]

={[P( Y ⋂ X) /P(X) ]*P(X)}/P(Y)

= P(Y ⋂ X)/P(Y) = P( X ⋂ Y)/P(Y) =P( X|Y)

Therefore to answer your question, yes Bayes Theorem is being taught in H2 Maths.

Hope this clarifies. Peace.

Best Regards,

Mr Koh