Ch. 9 Resources

Chapter 9: Regression Wisdom

Chapter 9 is largely a review of the things that might go wrong when you compute correlations and perform regression analyses, with some important new warnings about what not to do in certain situations. As such, there is really nothing new with regard to the TI-84 or Data Desk.

Homework

Work the following exercises in Chapter 9: 1, 5–15 odd, 21–27 odd and 31.

Errata

The scatterplot of the data in Exercise 24 shows the years listed as 80, 85, etc., but in the data set on the DVD (as well as the other information in this exercise) lists the years as 1980, 1985, etc.

ActivStats

Work the activities on pages 9-1 through 9-2 in the ActivStats lesson book, as time permits. We won't compute the statistic related to "leverage," but it is worth working through the activity associated with this term to understand the concept of leverage and which points are likely to be highly influential.

Additional Resources

Sofia: Elementary Statistics

Lesson 12.6 of the Sofia Open Content Initiative's Elementary Statistics course includes a discussion of outliers. (Some of the terminology may be unfamiliar here since this course covers regression far later in the game than we do.)

Anscombe's data sets

Four data sets to help convince you that you should always construct a scatterplot before computing the correlation coefficient or the equation of the regression line.

Regression applet

A Java applet to help visualize the influence of outliers on the regression line

GenderStats

Data from the World Bank on fertility rates and life expectancy for various countries, cited in Exercise 31.