Enjoying your day off?

We will go over the groupwork (1998 AP Problem) briefly in class on Wednesday, after your vocab quiz. This WILL NOT count as a classwork grade. You do not need to complete it.

So...I just finished making the vocab quiz for tomorrow...it has 9 new words (from chapter 8) and 3 from our chapter 7 test. Study! It turns out the vocab quiz is a little harder than I expected...just make sure you do some review! Study, study, study!

For homework, please answer the questions below, based on the following data/computer output:

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1. What is the value of the correlation coefficient (r)? 
2. Describe the correlation shown in the scatterplot above. Be sure to reference r.
3. Write the equation of the least squares regression line. Be sure to define any variables (context).
4. A plane with 350 seats had an operating cost of $6,500. Calculate the residual for a plane with this many seats.
5. Suppose you want to describe the relationship between operating cost per hour and number of passenger seats in the plane for planes only in the range of 250 to 350 seats. Does the line shown in the scatterplot still provide the best description of the relationship for data in this range? Why or why not?
6. Interpret the meaning of the slope, in context.
7. Interpret the meaning of the y-intercept, in context.
8. Interpret the meaning of the coefficient of determination, R^2, in context.
9. Use the scatterplot above to sketch a residual plot (# of passenger seats vs. residual).
10. Use your answer to number 9--does a linear model appear to be a good fit? Explain your reasoning.
11. Estimate the number of seats for the most expensive aircraft to operate.
12. Estimate the number of seats for the least expensive aircraft to operate.
13. Estimate the # of seats of the largest aircraft in this data set--approximately what was its operating cost?
14. Estimate the # of seats of the smallest aircraft in this data set--approximately what was its operating cost?