Joan has noticed that the probability distribution for X nu

Joan has noticed that the probability distribution for X = number of students in line to use the campus ATM machine when she shows up to use it is shown above. What is the probability that there will be no more than 2 students in line when Joan shows up? A) 0. 10 B) 0.20 C) 0.70 D)0.90 E) 0.60 The probability distribution for X = number of heads in 4 tosses of a fair coin is given In the table above. What is the value of the cumulative distribution function at 4, i.e. P(X

Solution

a)
P( no more than 2 students) = P(X=0)+P(X=1)+P(X=2)=0.10+0.10+0.40=0.50
b)
P(X<=4)=P(X=0)+P(X=1)+P(X=2)+P(X=3)+P(X=4) = 16/16