Steven Weber
Dept. of ECE
Drexel University
ENGR 361: Statistical Analysis of Engineering Systems (Spring, 2008)
Midterm Exam Solutions (Wednesday, April 30)
Instructions:
There are three problems. Each is worth 10 points. You have 50 minutes to complete the
exam. You are not to use any notes, books, or calculators. Partial credit is given for answers that are
partially correct. No credit is given for answers that are wrong or illegible. Write neatly.
Name:
Student ID #:
Signature:
Problem 1:
Problem 2:
Problem 3:
Total:
www.ece.drexel.edu/faculty/sweber
1
April 30, 2008
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Steven Weber
Dept. of ECE
Drexel University
Name:
Student ID #:
Score:
Problem 1 (10 points)
A gumball machine contains
100
gumballs, colored red, blue, and green. There are
27
red,
43
blue, and
30
green gumballs. Inserting a coin into the gumball machine yields a gumball. Each gumball
is equally likely to be selected for each inserted coin.
1.
(2 points)
What is the probability that of getting
3
red gumballs,
2
blue gumballs, and
5
green gumballs after
inserting the first
10
coins?
(
27
3
)(
43
2
)(
30
5
)
(
100
10
)
.
(1)
2.
(2 points)
What is the probability of not having a red gumball after inserting the first
10
coins?
(
73
10
)
(
100
10
)
.
(2)
3.
(2 points)
What is the probability of having exactly two colors of gumballs after inserting the first
10
coins?
(
43+30
10
)
+
(
27+43
10
)
+
(
27+30
10
)

(
27
10
)

(
43
10
)

(
30
10
)
(
100
10
)
.
(3)
4.
(1 point)
The person ahead of you inserts the first coin into the gumball machine and takes a gumball. She
gets a red gumball. What is the probability that you get a green gumball?
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '04
 Eisenstein
 Probability theory, 1966, 1973, 1946, Steven Weber

Click to edit the document details