Math 143 C/E, Spring 2001
IPS Reading Questions
Chapter 2, Section 3

1. What is the main use of a regression line (in particular, of its formula y = b₀ + b₁ x)?

   
   
   
   
   
   
   
   

2. If correlation determines how strongly linear a relationship between two quantitative variables is, what does regression do? Does the data have to look linear in its form in order to be able to perform regression?

   
   
   
   
   
   
   
   

3. Suppose you had a data set of n individuals which included two quantitative variables. Let us suppose that these two variables have a linear relationship - that is, that the first one, let's call it x, does a decent job of explaining the values of the other variable y. If you to find the equation of the regression line by hand, how would you go about it? Mention specifically which formulas you would use, the sequence you would use them in, and on which page(s) of your textbook the formulas are found.

   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

4. Suppose you knew two variables x and y were in a linear relationship and that the predicted value of y was 13.2 when the value of x was 5. If you wanted to know the predicted y-value when x = 5.5, then which would be necessary to know: the y-intercept b₀? the slope b₁? both? neither? Explain.