Sociology: Job Changes A sociologist is interested in the relation between x 5number of job changes and y 5annual salary (in thousands of dollars) for people living in the Nashville area. A random sample of 10 people employed in Nashville provided the following information:

x (Number of job changes)

4 7 5 6 1 5 9 10 10 3 y (Salary in

$1000)

33 37 34 32 32 38 43 37 40 33 Sx 5 60; Sy 5 359; Sx2 5 442; Sy2 513,013;

Sxy 5 2231

(a) Draw a scatter diagram for the data.

(b) Find x , y,

b, and the equation of the least-squares line. Plot the line on the scatter diagram of part (a).

(c) Find the sample correlation coefficient r and the coefficient of determination. What percentage of variation in y is explained by the least-squares model?

(d) Test the claim that the population correlation coefficient r is positive at the 5% level of significance.

(e) If someone had x 5 2 job changes, what does the least-squares line predict for y, the annual salary?

(f) Verify that Se < 2.56.

(g) Find a 90% confidence interval for the annual salary of an individual with x 5 2 job changes.

(h) Test the claim that the slope b of the population least-squares line is positive at the 5% level of significance.

(i) Find a 90% confidence interval for b and interpret its meaning.

AppendixLO1