Answer:
Step-by-step explanation:
Given that 85% of graduating students attend their graduation.
A group of 22 graduating students is randomly chosen.
X is the random variable representing no of students graduated form
X has two outcomes and also each student is independent of the other
a) X is Binomial with n=22 and p = 0.85
b) [tex]E(X) = np = 18.7[/tex]
c) probability that 17 or 18 attend.
=[tex]P(17)+P(18)\\=22C17 (0.85)^{17} (0.15)^5 +22C17 (0.85)^{18} (0.15)^4\\=0.3863[/tex]
d) [tex]P(X=22)=0.0127[/tex]
Since this is very near to zero it is unusual and we would be surprised.
