EXAMPLE 5.31
Counting software remote users. Your university supplies online remote access to various software programs used in courses. Suppose that the number of students remotely accessing these programs in any given hour can be modeled by a Poisson distribution with . What is the probability that more than 25 students will remotely access these programs in the next hour?
Calculating this probability requires two steps.
1. Write as an expression involving a cumulative probability:
2. Obtain and subtract the value from 1. Again using R,
The probability that more than 25 students will use this remote access in the next hour is only 0.028. Relying on software to get the cumulative probability is much quicker and less prone to error than the method of Example 5.30. For this case, that method would involve determining 26 probabilities and then summing their values.