practice_button.gif (2003 bytes)

Practice Materials for 'Uses' 2

1. This table reports 1993 College enrollment data by Age and Gender. How are the variables of student age and gender related?

College
Enrollment
(1000)

Males

Females

Total

18-19

1,224

1,416

2,640

20-21

1,294

1,414

2,708

30-34

661

811

1,472

over 35

955

1,824

2,779
All Ages

6,427

7,877

14,304


a. Find the probability that a student is female.
(Stan )Radio: a. 0.551 b. 0.657 c. 0.536

Possible answer

b. Find P (Student is Female given age18-19), the conditional probability an 18-19 years old college student is female.
(Stan )Radio: a. 0.10 b. 0.18 c. 0.536

Possible answer

c. Find P (Student is Female given age 35 and over), the conditional probability a college student age 35 and is Female.
(Stan )Radio: a. 0.657 b. 0.232 c. 0.128

Possible answer

d. Find P (age 35 and over given Female), the conditional probability a college student is age 35 given Female.
(Stan )Radio: a. 0.657 b. 0.232 c. 0.128

Possible answer

e. Are college student age and gender independent? Explain.
(Stan )Radio: a. Yes b. No c. Impossible to determine.

Possible answer

2.Two braking systems operate independently. Suppose the probability the first system fails is 0.002 and the probability the second system fails is 0.003.

What is the chance at least one set of brakes will work?
(Stan )Radio: a. 0.00006 b. 0.994 c. 0.999994

Possible answer

2

Copyright © 1999 CyberGnostics, Inc. All rights reserved.