# Question

The following data give information on the ages (in years) and the numbers of breakdowns during the last month for a sample of seven machines at a large company.

a. Taking age as an independent variable and number of breakdowns as a dependent variable, what is your hypothesis about the sign of B in the regression line? (In other words, do you expect B to be positive or negative?)

b. Find the least squares regression line. Is the sign of b the same as you hypothesized for B in part a?

c. Give a brief interpretation of the values of a and b calculated in part b.

d. Compute r and r2 and explain what they mean.

e. Compute the standard deviation of errors.

f. Construct a 99% confidence interval for B.

g. Test at a 2.5% significance level whether B is positive.

h. At a 2.5% significance level, can you conclude that p is positive? Is your conclusion the same as in part g?

a. Taking age as an independent variable and number of breakdowns as a dependent variable, what is your hypothesis about the sign of B in the regression line? (In other words, do you expect B to be positive or negative?)

b. Find the least squares regression line. Is the sign of b the same as you hypothesized for B in part a?

c. Give a brief interpretation of the values of a and b calculated in part b.

d. Compute r and r2 and explain what they mean.

e. Compute the standard deviation of errors.

f. Construct a 99% confidence interval for B.

g. Test at a 2.5% significance level whether B is positive.

h. At a 2.5% significance level, can you conclude that p is positive? Is your conclusion the same as in part g?

## Answer to relevant Questions

The health department of a large city has developed an air pollution index that measures the level of several air pollutants that cause respiratory distress in humans. The accompanying table gives the pollution index (on a ...Briefly explain the assumptions of a regression model. A magazine published a questionnaire for its readers to fill out and mail to the magazine’s office. In the questionnaire, cell phone owners were asked how much they would have to be paid to do without their cell phones for ...Refer to Exercise A.25. Suppose the physicians conducting this study obtained a list of all patients suffering from compulsive behavior who were being treated by doctors in all hospitals in the country. Further assume that ...A group of veterinarians wants to test a new canine vaccine for Lyme disease. (Lyme disease is transmitted by the bite of an infected deer tick.) One hundred dogs are randomly selected to receive the vaccine (with their ...Post your question

0