# statistic

## statistic

• Submitted By: cibot
• Date Submitted: 05/07/2014 6:07 PM
• Words: 1026
• Page: 5

DM Statistics
Exercise 1:
The automobile industry sold 657,000 vehicles in the United States during January 2009 (The
Wall Street Journal, February 4, 2009). This volume was down 37% from January 2008 as
economic conditions continued to decline. The Big Three U.S. automakers— General Motors,
Ford, and Chrysler—sold 280,500 vehicles, down 48% from January 2008. A summary of
sales by automobile manufacturer and type of vehicle sold is shown in the following table.
Data are in thousands of vehicles. The non-U.S. manufacturers are led by Toyota, Honda, and
Nissan. The category Light Truck includes pickup, minivan, SUV, and crossover models.

Type of Vehicle

Car

Manufacturer

87.4

U.S.
Non U.S.

Light Truck
193.1

228.5

148.0

a. Develop a joint probability table for these data and use the table to answer the
remaining questions.
Type of Vehicle
Car

Light Truck

87.4

193.1

280.5

Non U.S.

228.5

148.0

376.5

TOTAL

315.9

341.1

657.0

U.S.
Manufacturer

TOTAL

A total of 657.0 thousand vehicles were sold.
Dividing each entry in the table by 657.0 provides the following joint probability table.
Type of Vehicle
Car
U.S.

0.1330

0.2939

0.4269

Non U.S.

0.3478

0.2253

0.5731

TOTAL

Manufacturer

Light Truck

TOTAL

0.4808

0.5192

1.0000

FOUASSON
Pierre-­‐Emmanuel
VOIGNER
Marjolaine

ESC2
Mineure
International
Corporate
Finance

b. What are the marginal probabilities? What do they tell you about the
probabilities associated with the manufacturer and the type of vehicle sold?
U= U. S. manufacturer
N= Non U.S. manufacturer
C= Car
L= Light Truck
Marginal probabilities : P(U)=0.1330+0.2939= 0.4269
P(B)=0.3478+0.2253= 0.5731
There a higher probability that the vehicle was not manufactured by a U.S auto maker. In
terms of market share, non US. Auto...