1. MULTIPLE AND PARTIAL CORRELATION INVOLVING FOUR OR MORE VARIABLES
Show that the regression equation of x4 on x1, x2, and x3 can be written
2. Find (a) r41:23, (b) r42:13, and (c) r43:12 for the data of Problem 15.42 and interpret your results.
3. The amount spent on medical expenses per year is correlated with other health factors for 15 adult males.
A study collected the medical expenses per year, Y, as well as information on the following independent variables,
x2 = money spent on alcohol per week;
The notation given in this problem will be encountered in many statistics books. Y will be used for the dependent variable and X with subscripts for the independent variables. Using the data in Table 15.6, find the regression equation of Y on X1 through X6 by solving the normal equations and contrast this with the EXCEL, MINITAB, SAS, SPSS, and STATISTIX solutions.
Medcost
Smoker
Alcohol
Exercise
Dietary
Weight
Age
2100
0
20
5
1
185
50
2378
1
25
0
1
200
42
1657
0
10
10
2
175
37
2584
1
20
5
2
225
54
2658
1
25
0
1
220
32
1842
0
0
10
1
165
34
2786
1
25
5
0
225
30
2178
0
10
10
1
180
41
3198
1
30
0
1
225
31
1782
0
5
10
0
180
45
2399
0
25
12
2
225
45
2423
0
15
15
0
220
33
3700
1
25
0
1
275
43
2892
1
30
5
1
230
42
2350
1
30
10
1
245
40