Solution Found!
Suppose that a school has 20 classes: 16 with 25 students
Chapter 2, Problem 10E(choose chapter or problem)
Problem 12E
Suppose that a school has 20 classes: 16 with 25 students in each, three with 100 students in each, and one with 300 students, for a total of 1000 students.
(a) What is the average class size?
(b) Select a student randomly out of the 1000 students. Let the random variable X equal the size of the class to which this student belongs, and define the pmf of X.
(c) Find E(X), the expected value of X. Does this answer surprise you?
Questions & Answers
QUESTION:
Problem 12E
Suppose that a school has 20 classes: 16 with 25 students in each, three with 100 students in each, and one with 300 students, for a total of 1000 students.
(a) What is the average class size?
(b) Select a student randomly out of the 1000 students. Let the random variable X equal the size of the class to which this student belongs, and define the pmf of X.
(c) Find E(X), the expected value of X. Does this answer surprise you?
ANSWER:
Answer :
Step 1 of 3 :
Given, a school has 20 classes, 16 with 25 students in each, 3 with 100 students in each, and 1 with 300 students.
We have total of 1000 students.
- The claim is to find the average class size
For x = 25, the number of students = 16(25)
= 400
For x = 100, the number of students = 3(100)
= 300
For x = 300, the number of students = 1(300)
= 300
Average class size =
= 40