Problem session for Chapter 3 in class exercises

See Sec4.1.ppt

- Added variables plot

R LAB

- Complete the variable added plot handout.

Please read Section 4.2 for class on Wednesday.

We will have our second quiz in class on Friday. The quiz will cover the material in Sections 2.4 and 2.5, Chapter 3, and as far as we get in Chapter 4 by the end of class on Wednesday. The ground rules will be the same as Quiz #1.