Exercise 12-12 Mr. James McWhinney, president of Daniel-James Financial Services
ID: 3355715 • Letter: E
Question
Exercise 12-12
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 Y column shows the value of sales ($ thousands) last month for each client sampled. (Round the final answers to 2 decimal places.)
Determine the standard error of estimate.
Suppose a large sample is selected (instead of just 10). About 68% of the predictions regarding sales would occur between what two values? Assuming that the Standard Error of Estimate does not change. Use z = 1.
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 Y column shows the value of sales ($ thousands) last month for each client sampled. (Round the final answers to 2 decimal places.)
Explanation / Answer
A)
x
x2
y
y2
xy
37
1369
51
2601
1887
15
225
22
484
330
42
1764
62
3844
2604
50
2500
84
7056
4200
19
361
26
676
494
38
1444
69
4761
2622
25
625
45
2025
1125
12
144
35
1225
420
15
225
30
900
450
19
361
29
841
551
Average
27.2
45.3
Sum
272
9018
453
24413
14683
Regression equation is:
=14683-((272*453))/10
= 2361.4
= 9018-((272*272))/10
= 1619.6
=2361.4/1619.6
=1.4580
= 45.3-(1.4580*27.2)
= 5.6424
The regression equation is:
=-5.6424 + 1.4580x
x
x2
y
y2
xy
37
1369
51
2601
1887
15
225
22
484
330
42
1764
62
3844
2604
50
2500
84
7056
4200
19
361
26
676
494
38
1444
69
4761
2622
25
625
45
2025
1125
12
144
35
1225
420
15
225
30
900
450
19
361
29
841
551
Average
27.2
45.3
Sum
272
9018
453
24413
14683
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