Fiesta 5 Chapter 2 Web

AP STATISTICS | FIESTA 5 | FALL 2008 | SHUBLEKA    

NAME__________________________ Use full English sentences and write your answers on a separate page. Show all your work for full credit. Problem 1 Coffee is a leading export from several developing countries. When coffee prices are high, farmers often clear forest to plant more coffee trees. Here are data on prices paid to coffee growers in Indonesia and the rate of deforestation in a national park that lies in a coffee-producing region for five years: Price (cents/pound) Deforestation (percent)

29 0.49

40 1.59

54 1.69

55 1.82

72 3.10

a) Make a scatterplot. Which is the explanatory variable? What pattern does your plot show? b) Find the correlation r step-by-step using lists 1 through 5 in your graphing device. Be certain to explain each step using full sentences. c) Use the correlation from part b) and other one-variable statistics to determine the Least Squares regression line. Show the work leading to your answer. d) Find the Least Squares regression line using your graphing device. Compare your answer to the result in part c). e) Interpret the meaning of slope and y-intercept. f) Suppose you determine that your choice of explanatory and response variables needs to be changed so that the original explanatory variable becomes a response variable and vice-versa. How would this affect the equation of your regression line? Explain. Problem 2 A study of class attendance and grades among first-year students at a state university showed that in general students who attended a higher percent of their classes earned higher grades. Class attendance explained 16% of the variation in grade index among the students. What is the numerical value of the correlation between percent of classes attended and grade index? Explain.