Is there a strong correlation between the number of miles driven by a salesperson and sales volume achieved? Data were gathered from nine salespeople who worked territories of similar size and potential. Determine the correlation coefficient for these data. Assume the data are ordinal in level of measurement.

Sales Miles per Month

$150,000 ...........1,500

210,000 ...........2,100

285,000 ...........3,200

301,000 ...........2,400

335,000 ...........2,200

390,000 ...........2,500

400,000 ...........3,300

425,000 ...........3,100

440,000 ........... 3,600