Interview Q&A / Data Science

1. How do you calculate conditional probability from a two-way table?

   P(A given B) is the count of A-and-B divided by the count of B. You restrict attention to the rows or columns where B is true and compute the share there. P(A given B) is not the same as P(B given A).

   BeginnerQuick answer1 min read
2. How does Bayes theorem work? Explain with a medical test example.

   Bayes theorem updates a probability using new evidence: P(A|B) = P(B|A) x P(A) / P(B). It shows that a positive result from an accurate test can still mean a low chance of disease when the disease is rare.

   IntermediateQuick answer1 min read