Unit 5: Regression

Text reading and review exercises:

Review chapters 10, 11, and 12 of FPP and do the following review exercises:
Chapter 10 [pages 176-178]: 2, 3, 4, 7, 8, 9, 10
Chapter 11 [pages 198-201]: 2, 3, 4, 6, 9, 10
Chapter 12 [pages 213-216]: 2, 4, 5, 6

Reading:

"Conditional cash transfer: a magic bullet for health?" by Kenji Shibuya, The Lancet, March 8, 2008, page 789.

Document source: LexisNexis.

Possible essay questions:

This article reads like the "Discussion and Conclusion" section of our of our final projects. What information would appear in earlier parts of the project. Would such information have been helpful to you in appreciating this research?
Is CCT frequently used in the U.S.?

Computer project:

Boy Scouts and Girl Scouts are taught that a way to measure temperature is by counting cricket chirps and applying a formula to find the temperature. The data in the following reference gives the number of cricket chirps in a 15-second period and the temperature in degrees Farenheit at that time: Data on cricket chirps vs. temperature.

Copy the data above into a spreadsheet program, with the temperatures in the left column and the numbers of chirps in a 15-second period in the right column.
Create a scatter plot for the data. Put Temperature on the horizontal axis and Chirps per Period on the vertical axis.
In a sentence or two, describe the association that exists between the two variables. What type of association (linear, curvilinear or none? positive or negative?) is present? How strong is the association? (Type this into your spreadsheet so that it will come out when you print.)
Have the spreadsheet compute the averages and standard deviations of each variable and the correlation coefficient between them. Create a third column that contains values on the SD-line for each temperature value. (See the link below for help in getting this data from Excel.)
Have Excel compute the slope and y-intercept of the regression line for Chirps per Period on Temperature. Label these values appropriately.
Create a fourth column to hold a list of "predicted" chirps per period values (lying on the regression line).
Create a scatter diagram of the data that includes plots of the SD-line and the regression line for Chirps per Period vs Temperature. Change the style for the data points that represent the lines to actual lines (double-click on the data point and turn on lines and turn off markers).
Which is steeper, the SD-line or the regression line? Does this make sense? Why?

Excel instructions for finding the SD-line and regression line can be found in the supplement Using Excel 2: Slope and Intercept of Regression Lines