Sales and profits - A business analyst was interested in the relationship between a company's sales and its profits. She collected data (in millions of dollars) from a random sample of Fortune 500 companies and created the regression analysis and summary statistics shown. The assumptions for regression inference appeared to be satisfied.

a) Is there a statistically significant association between sales and profits? Test an appropriate hypothesis and state your conclusion in context.

b) Do you think that a company's sales serve as a useful predictor of its profits? Use the values of both R^2 and s in your explanation

50. More sales and profits - Consider again the relationship between the sales and profits of Fortune 500 companies that you analyzed in Exercise 48.

a) Find 95% confidence interval for the slope of the regression line. Interpret your interval in context.

b) Last year, the drug manufacturere Eli Lilly, Inc, reported gross sales of $23 billion (that's $23,000 million). Create a 95% prediction interval for the company's profits, and interprett your interval in context.

c) Create and interpret 95% confidence interval for the mean profit for gross sales of $23 billion.

Thank you so much!! help very needed!