I'm trying to understand this problem and could do with some help. A small business is trying to measure their delivery performance in terms of "on-time, in-full & error-free". It sent out product to 4 customers (A,B,C,D) and notes down what the performance was: 0 = not ok, 1 = ok. (Apologies for not being able to do a table) __________A_B_C_D on time____1_0_1_1 in full______1_1_1_0 error free___0_1_1_1 Overall_____0_0_1_0 It is clear that only 1 out of 4 (25%) actually received goods on-time, in-full & error-free. But then, a customer calls Sales and asks "What are the chances of my order being on-time in full and error-free? The Sales guy thinks to himself: Well, 3 out 4 (75%) were on time, 75% were in full & 75% were error-free so the chances are: 0.75 x 0.75 x 0.75 = 0.42 and tells the customer "There is a 42% chance your order will be on-time, in-full & error-free" Can anybody explain why there is such a difference between the actual performance and the probability? Thanks in advance.