Unit 5: Regression Analysis

Text reading and homework:

Read 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


"It's Always the Economy, Stupid: To win in November, focus on paychecks, not polls" by Ezra Klein, Newsweek, July 19, 2010, page 22.
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Possible essay questions:

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 reference below give 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
  1. 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.
  2. Create a scatter plot for the data. Put Temperature on the horizontal axis and Chirps per Period on the vertical axis.
  3. 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 excel or write it on your printout when you get it.)
  4. Have the spreadsheet compute the averages and standard deviations of the columns and the correlation coefficient between them. Label these values as such in the spreadsheet. Have it place in a third column (say, next to the other two), a list of "Chirps per Period" values that lie on the SD-line directly above or below (i.e., at the same "Temperature" values of) the data points. (See the link below for help in getting this data from Excel.)
  5. Have the spreadsheet compute the slope and y-intercept of the regression line for Chirps per Period on Temperature. Label these values appropriately.
  6. Create a fourth column D consisting of a list of "predicted" chirps per period values (lying on the regression line).
  7. Create a second scatter diagram of the data that includes plots of the data, the SD-line and the regression line for Chirps per Period on Temperature. Change the style for the data points that represent the lines to lines (double-click on the data point and turn on lines and turn off symbols).
  8. Which is steeper, the SD-line or the regression line? Does that make sense? Why?

Excel instructions for finding the SD-line and regression line.