statistics
posted by ashley .
1. Suppose the number of students in line during office hours:
# of Students (X) Probability P(X)
0 0.40
1 0.30
2 ????
3 0.10
a. If you knew that the number of students in line was between 0 and 3, what is the probability that will be 2 students in line when you arrive at the office

Total probability of all events = 1.
.4 + .3 + ? + .1 = 1