Use the StatDisk output and scatter plot from the previous page to answer the following questions. The data is printer cost versus printing speed, just like the activity from earlier in the semester.

Part One:

Describe the form, direction, and strength of the relationship?

Find the correlation coefficient for this relationship.

What proportion of variation can be explained by the linear relationship between the

two variables?

Write the equation for the least squares line for this relationship.

Use the equation to predict the price for a printer that prints at a rate of 2 pages per

minute. Is this an appropriate use of this model? Explain.

Use the equation to predict the printing speed of a printer that costs $400. Is this an

appropriate use of this model? Explain.

Do we have evidence that there is a relationship between price and printing speed? How can you tell?

Part Two: It appears our printer data was inadvertently mixed with scanner data, which created 6 outliers. After verifying that the scanners were included in error, the outliers have been removed from the data. Here are the correlation/regression results based on the updated data.

Correlation Results: Correlation Coeff, r: 0.68477 Coeff of Det, R^2: 0.468891

Should the outliers have been removed? Why or why not?

Has the strength of relationship increased or decreased? How can you tell?

What proportion of variation can be explained by the linear relationship between the

two variables? Has that increased or decreased since the outliers have been removed?

Do we have evidence that there is a relationship between price and printing speed now

that the outliers have been removed? How can you tell?