With the poisson formula in statistics, I am having trouble answering this question:

According to a study conducted by the depart- ment of Pediatrics at the University of California, San Francisco, children who are injured two or more times tend to sustain these injuries during a relatively limited time, usually 1 year or less. Assume the average number of injuries per year for school-age children is two.

1. Find the probability of a school-age child sustains two injuries during the year.
2. Find the probability of a school-age child sustains two or more injuries during the year.
3. Find the probability of a school-age child sustains at most one injuries during the year.
4. Calculate the mean and standard deviation for x, the number of injuries per year sustained by a school-age child.