Fall Semester 2003

Our seventh time in lab, Wednesday November 19, 2003
Date
Nov 19, 2003

Due today
Reading Assignment: Chapter 8 (Regression and Correlation) in the text.

Starting today
LAB ASSIGNMENT FIVE (the questions listed below).

Due next time (a week from today)
Reading Assignment: Chapter 9 (Multiple Regression) in the text.

What is the lab assignment?
Answer the questions below also indicating the page(s) in the book where the answer can be found.

When is it due?
Check the What's Due? page for details.

What's the best approach to this assignment?
Read the book, work through all the experiments.

Here are the questions

Chapter 8: Regression and Correlation.

1. What can you calculate using the Excel functions INTERCEPT and SLOPE? How? Give an example.

2. The workbook BCancer.xls contains data from a 1965 study analyzing the relationship between mean annual temperature and the mortality rate for a certain type of breast cancer in women. The subjects came from 16 different regiones in Great Britain, Norway, and Sweden. You've been asked to determine whether there is evidence of a linear relationship between the mean annual temperature in the region and the mortality index. Is the mortality index different for women who live in regions with different temperatures? Explain your answer.

3. Quote from the book: "One point that cannot be emphasized too strongly is that a significant regression is not proof that these assumptions haven't been violated. To verify that your data does not violate these assumptions is to go through a series of tests, called diagnostics." What assumptions does the quote refer to? Do you need to run any diagnostics with respect to your answer at the previous question? Why and how would you do that (if you have to).

4. What's Spearman's rank correlation coefficient and why (or when) might we be better off using it instead of Pearson's?

5. Consider the Calc.xls workbook. This file contains data collected to see how performance in a freshman calculus class is related to various predictors. Analyze the workbook and answer the following question: can you say that taking calculus in high school causes a better grade in college? Is there any relationship between taking calculus in high school and getting good grades in college? What is it? Explain your answers.

6. For which variables in the workbook from the previous question is it reasonable to say that correlation and linear regression are appropriate when predicting whether calculus has been taken in high school or not?

Last updated: Nov 10, 2003 by Adrian German for A113