2.146 Sales and production. Refer to the previous two exercises.

1. (a) Make a scatterplot with sales as the response variable and production as the explanatory variable. Describe the relationship. Are there any outliers or influential observations?

2. (b) Find the least-squares regression line and add it to your plot.

3. (c) Interpret the slope of the line in the context of this exercise.

4. (d) Interpret the intercept of the line in the context of this exercise. Explain whether or not this interpretation is useful in explaining the relationship between these two variables.

5. (e) What is the predicted value of sales for a country that has an index of 109 for production?

6. (f) The Netherlands has an index of 109 for production. Find the residual for this country.

7. (g) What percent of the variation in sales is explained by production? How does this value compare with the percents of variation that you calculated in the two previous exercises?