Profit. How are a company s profits related to its sales? Let s examine data from 71 large U.S. corporations. All amounts are in millions of dollars. a) Here are histograms of Profits and Sales and...

Profit. How are a company s profits related to its sales? Let s examine data from 71 large U.S. corporations. All amounts are in millions of dollars.

a) Here are histograms of Profits and Sales and histograms of the logarithms of Profits and Sales. Why are the re-expressed data better for regression?

b) Here are the scatterplot and residuals plot for the regression of logarithm of Profits vs. log of Sales. Do you think this model is appropriate? Explain.

c) Here’s the regression analysis. Write the equation.

d) Use your equation to estimate profits earned by a company with sales of 2.5 billion dollars. (That s 2500 million.)