Math 143 C/E, Spring 2001
IPS Reading Questions
Chapter 2, Section 2

1. What does the correlation r tell us?

   
   
   
   
   
   
   
   

2. Suppose you had a data set for n individuals for which had been recorded their heights (in feet) and their foot length heel to toe (in inches). Suppose also that the scatterplot made it appear that the relationship between the two variables was a strong linear one, and that the correlation value confirmed this (by being close to 1). What effect on r would result from

   • converting all of the heights to inches and recalculating the correlation?
   • adding to the data one more observation that lay well off of the regression line?

   
   
   
   
   
   
   
   

3. Read Example 2.10, p. 130. A correlation r = 0.9 indicates a fairly strong linear relationship between scores given by Ivan and George. Let x and y represent the scores given out by Ivan and George respectively. What would be a likely formula for an equation relating x and y? Is this an equation of a line?