The manager of Colonial Furniture has been reviewing weekly advertising expenditures. During the past 6 months, all advertisements for the store have appeared in the local newspaper. The number of ads per week has varied from one to seven. The store’s sales staff has been tracking the number of customers who enter the store each week. The number of ads and the number of customers per week for the past 26 weeks were recorded. In your opinion, is it a worthwhile exercise to use the regression equation to predict the number of customers who will enter the store, given that Colonial intends to advertise five times in the newspaper? If so, find a 95% prediction interval. If not, explain why not.

The manager of Colonial Furniture has been reviewing weekly advertising expenditures. During the past 6 months, all advertisements for the store have appeared in the local newspaper. The number of ads per week has varied from one to seven. The store’s sales staff has been tracking the number of customers who enter the store each week. The number of ads and the number of customers per week for the past 26 weeks were recorded. Determine the sample regression line.

Fire damage in the United States amounts to billions of dollars, much of it insured. The time taken to arrive at the fire is critical. This raises the question, Should insurance companies lower premiums if the home to be insured is close to a fire station? To help make a decision, a study was undertaken wherein a number of fires were investigated. The distance to the nearest fire station (in miles) and the percentage of fire damage were recorded. Determine the least squares line and interpret the coefficients

Calculate and plot the residuals and predicted values of y for Exercise 16.5.

Besides their known long-term effects, do cigarettes also cause short-term illnesses such as colds? To help answer this question, a sample of smokers was drawn. Each person was asked to report the average number of cigarettes smoked per day and the number of days absent from work due to colds last year. What do the coefficients tell you about the relationship between smoking cigarettes and sick days because of colds?

Calculate the residuals and predicted values of y in Exercise 16.3.

Refer to Exercise 16.2. Calculate the residuals and the predicted values of y.

Besides their known long-term effects, do cigarettes also cause short-term illnesses such as colds? To help answer this question, a sample of smokers was drawn. Each person was asked to report the average number of cigarettes smoked per day and the number of days absent from work due to colds last year. Determine the regression line

You are given the following six points:

$$\begin{array}{rrrrrrr}x & -5 & -2 & 0 & 3 & 4 & 7 \\ y & 15 & 9 & 7 & 6 & 4 & 1\end{array}$$

Determine the regression equation.

If (0.57, 0.63) is a 50% confidence interval for p, what does $\frac{k}{n}$ equal, and how many observations were taken?

An insurance company is thinking about offering discounts on its life insurance policies to nonsmokers. As part of its analysis, the company randomly selects 200 men who are 60 years old and asks them whether they smoke at least one pack of cigarettes per day and if they have ever suffered from heart disease. (2 = Suffer from heart disease, 1 = Do not suffer from heart disease). Estimate with 90% confidence the difference in the proportions of men suffering from heart disease between smokers and nonsmokers.

These statistics were calculated from two random samples:

$$\hat{p}_1=.60 \quad n_1=225 \quad \hat{p}_2=.55 \quad n_2=225$$

Calculate the p-value of a test to determine whether there is evidence to infer that the population proportions differ

High blood pressure (hypertension) is a leading cause of strokes. Medical researchers are constantly seeking ways to treat patients suffering from this condition. A specialist in hypertension claims that regular aerobic exercise can reduce high blood pressure just as successfully as drugs, with none of the adverse side effects. To test the claim, 50 patients who suffer from high blood pressure were chosen to participate in an experiment. For 60days, half the sample exercised three times per week for 1 hour and did not take medication; the other half took the standard medication. The percentage reduction in blood pressure was recorded for each individual. Estimate with 95% confidence the difference in mean percentage reduction in blood pressure between drugs and exercise programs.

An insurance company is thinking about offering discounts on its life insurance policies to nonsmokers. As part of its analysis, the company randomly selects 200 men who are 60 years old and asks them whether they smoke at least one pack of cigarettes per day and if they have ever suffered from heart disease. (2 = Suffer from heart disease, 1 = Do not suffer from heart disease).. Can the company conclude at the 10% significance level that smokers have a higher incidence of heart disease than nonsmokers?