3. In an effort to decide if there is an association between the year of a postal increase and the new postal rate for first class mail, the data were gathered from the United States Postal Service. In 1981, the USPS changed their rates on March 22 and November 1. This information is shown in the table below. Year 1971 1974 1975 1978 1981 1981 1985 1988 1991 1995 Rate 0.08 0.10 0.13 0.15 0.18 0.20 0.22 0.25 0.29 0.32 a. Draw a scatterplot by hand, labeling both axes as well as the scales. (3 points) b. Which is the explanatory variable, and which is the response variable? (1 point) c. Describe the association (direction, strength, and form) between the year and the first- class postal rates. (3 points) d. Calculate the correlation coefficient. Round to three decimal places. Explain how this supports your description in part c. (2 points) e. Create a model to predict postal rates from the year. Round to two decimal places. (2 points) f. Do you think a linear model is appropriate here? Explain. (1 point) 4. An 8th grade class develops a linear model that predicts the number of cheerios that fit on the circumference of a plate by using the diameter in inches. Their model is =0.56+5.11(). a. Interpret the slope of your model in context. (2 points) b. Interpret the intercept of your model in context. Does this interpretation make sense? Why or why not? (3 points) c. If the diameter is increased from 4 inches to 14 inches, the predicted number of cheerios will increase by what amount? (1 point) d. The observed number of cheerios for a plate with a diameter of 11 inches is 51. What is the predicted number of cheerios for a plate with a diameter of 11? (1 point) e. Find the residual for a plate with a diameter of 11 and interpret its meaning. (2 points)