Discrete Probability Distributions
Binomial Distribution b(n ,p)

In the previous example, on average, we expect 7*0.9 = 6.3 patients to survive this operation.  This means that if we observe a large number of batches of patients, each consisting of 7, and recorded the number of survivors in each batch, the arithmetic average of the recorded survivors will tend to 6.3 as the number of batches gets larger.

Similarly, P[5] = 0.124  means that if we observe a large number of batches of patients, each consisting of 7, the number of times exactly 5 survive will tend to 12.4% of all observed batches as the number of batches gets larger.                                                              L. K. Gaafar