Question

To determine the effect of advertising in the Yellow Pages, Bell Telephone took a sample of 40 retail stores that did not advertise in the Yellow Pages last year but did so this year. The annual sales (in thousands of dollars) for the same store in both years were recorded and are shown below. Bell would like to know if the average sales for this year are greater than the average sales for last year. A) State the Null and Alternative Hypotheses. B) Is this a left-tailed, right-tailed, or two-tailed test? C) Run an appropraite t-test (use 5% level of significance); use cell G27 for your output. D) Change correct p-value to a % and highlight yellow. Make a decision based on your t-test results.

Store #	This Year	Last Year
1	189	151
2	225	224
3	106	30
4	146	132
5	234	233
6	233	213
7	210	197
8	107	81
9	213	209
10	174	165
11	209	208
12	237	251
13	190	144
14	159	154
15	176	160
16	145	96
17	294	257
18	141	81
19	197	166
20	156	170
21	167	257
22	224	231
23	250	195
24	210	221
25	257	211
26	197	183
27	203	180
28	190	127
29	202	170
30	191	177
31	249	236
32	196	154
33	183	143
34	192	168
35	217	154
36	104	102
37	275	242
38	137	82
39	128	148
40	159	179

Answer 1

Let us denote the difference

d = sales this year - sales last year