Before you look at some data what kind of association do you

Before you look at some data, what kind of association do you think will exist between the weight of a car and the miles per gallon that the car gets? Will it be positive or negative?

Given the data below, use Excel or other technology to calculate the correlation coefficient for this data:

Model

City MPG

Weight

Mazda MX-5 Miata

25

2365

Mercedes/Benz SLK

22

3020

Mitsubishi Eclipse

23

3235

Pontiac Firebird

18

3545

Porsche Boxster

19

2905

Saturn SC

27

2420

Answer the following questions in a Word document:

Now that you have calculated the correlation, what does this value represent? What does it tell you about the relationship between these two variables?

Solution

As the weight of the car increase, the millage (miles per gallon) decrease. So there should be linear and negative relationship between the variables City MPG and weight.

The correlation coeffcient between the variables, comuted by excel is : -0.79454

Since correlation coeffcient is negative so it shows a strong, linear and negative relationship between the variables.