Question

Mr. James McWhinney, president of Daniel-James Financial Services, believes there is a relationship between the number of client contacts and the dollar amount of sales. To document this assertion, Mr. McWhinney gathered the following sample information. The x column indicates the number of client contacts last month and the ycolumn shows the value of sales ($ thousands) last month for each client sampled. (Round your answers to 3 decimal places.)

Number of Contacts, x		Sales ($ thousands), y		Number of Contacts, x		Sales ($ thousands), y
14		24		23		30
12		14		48		90
20		28		50		85
16		30		55		120
46		80		50		110

1. Determine the 0.95 confidence interval, in thousands of dollars, for the mean of all sales personnel who make 40 contacts.

2. Determine the 0.95 prediction interval, in thousands of dollars, for a particular salesperson who makes 40 contacts.

Answer 1

The statistical software output for this problem is:

Hence,

a) 95% confidence interval:

(68.289, 82.881)

b) 95% prediction interval:

(52.909, 98.260)