The assistant to the regional manager of a mid-size paper company wants to know if his subordinates waste time on their personal email accounts instead of using their work email. To address the question, he has his cousin who works on his beet farm collect data on each of the 20 employees. The data below shows the average number of emails each employee (subordinate) sends in a week for both personal and work email accounts.

Employee	Personal	Work	Difference
1	19	21	-2
2	16	20	-4
3	17	20	-3
4	14	21	-7
5	17	26	-9
6	16	25	-9
7	19	17	2
8	18	23	-5
9	15	23	-8
10	18	24	-6
11	15	25	-10
12	16	17	-1
13	16	25	-9
14	14	24	-10
15	13	26	-13
16	17	23	-6
17	19	23	-4
18	17	23	-6
19	14	23	-9
20	13	22	-9
Average	16.15	22.55	-6.4
St. Dev.	1.93	2.58	3.63

What is the parameter of interest?

Calculate a 95% confidence interval for the parameter of interest. (show work)

Interpret the confidence interval