Final answer:
To find P(B|A), the formal approach is by using mathematical formulas, specifically Bayes' theorem, to calculate the conditional probability of B given A.
Step-by-step explanation:
The formal approach for finding P(B|A), which is the probability of event B occurring given that event A has occurred, is by using mathematical formulas (Option A). This approach is based on Bayes' theorem and involves calculating the probability of both events A and B occurring, divided by the probability of A occurring. It's important to focus on understanding the concept behind the equation, as this will lead to a more permanent grasp of the material beyond just memorization. This method is different than relying on personal feelings and instincts (Option B), conducting experiments and collecting data (Option C), or consulting statistical experts for guidance (Option D), which can be complementary but are not direct methods for calculating conditional probabilities.