At a telephone enquiry system, the number of phone calls regarding relevant enquiry follows a Poisson distribution with an average of phone calls during time intervals. The probability that there is at most one phone call during a time period is:
- A
- B
- C
- D
Solution & Step-by-step Explanation
For a Poisson distribution, , where is the mean.Here, .We need to find . Sum .This can also be written as .