Business Statistics for Managerial Decision. Probability Theory. Probability Theory. The mathematics of probability can provide models to describe
P(A or B) = P(A) + P(B)
P(A or B) = P(A) + P(B) - P(A and B)
P(A and B) = P(A) × P(B)
varies in many samples.
changes shape: it looks less like that of the population distribution and more like a Normal distribution.