(Solved by Humans)-) Use the dataset low_birth_weight_infants.dta . (1.5) Do a

Question

) Use the dataset low_birth_weight_infants.dta.?

1. (1.5) Do a linear regression to model birth weight as the dependent variable and gestational age as the independent variable:

The equation is: _____________________

The coefficient of determination is: ______________________

The p-value for the slope is: ___________________

1. (2.5) Add length as another independent variable to the above regression model.

The equation is: _____________________

The coefficient of determination is: ______________________

The p-value for the gestage coefficient is: ___________________

The p-value for the length coefficient is: ___________________

Do you think the model improves by adding length as an independent variable (yes/no) _____? Explain.

1. (2) Compute a 95% confidence interval for the true mean of birth weight with a gestational age of 31 weeks and a length of 40 cm. Round off to whole numbers.
2. (2) Create an interaction term by multiplying gestational age and length. Add the interaction term to the model that already includes gestage and length. Fill in the table (left column without interaction, right column with interaction term).

	Independent variables
	gestage, length	gestage, length, gestlength
p-value, gestage coefficient
Std error, gestage coefficient
p-value, length coefficient
Std error, length coefficient
Coefficient of determination

1. (1) What principle accounts for the changes in p-value and standard error?
2. (1) Since the coefficient of determination rose slightly, would you include the interaction term in the model? Why or why not?

headcirc length
gestage birthwt
momage toxemia
27
41
29
1360
37
0
29
40
31
1490
34
0
30
38
33
1490
32
0
28
38
31
1180
37
0
29
38
30
1200
29
1
23
32
25
680
19
0
22
33
27
620
20
1
26
38
29
1060
25
0
27
30
28
1320
27
0
25
34
29
830
32
1
23
32
26
880
26
0
26
39
30
1130
29
0
27
38
29
1140
24
0
27
39
29
1350
26
0
26
37
29
950
25
0
27
39
29
1220
25
0
26
38
29
980
28
0
29
42
33
1480
30
0
28
39
33
1250
31
1
27
38
29
1250
37
0
25
36
28
920
31
0
25
38
30
1020
21
0
24
34
27
750
21
0
31
42
33
1480
30
0
28
37
32
1140
23
0
23
32
28
670
33
1
26
36
29
1150
18
0
25
34
28
1030
20
0
23
33
29
560
29
0
28
37
30
1260
26
0
35
36
31
900
23
0
24
31
30
620
33
0
33
39
31
1440
26
0
28
39
29
1350
38
0
26
37
27
1170
23
0
26
36
27
1170
23
0
26
37
27
1170
26
0
28
40
32
1420
27
0
29
43
31
1475
27
0
28
37
28
1200
19
0
27
36
30
970
30
1
27
38
29
1190
27
0
28
39
28
1350
31
0
28
41
31
1460
29
0
22
32
27
570
23
1
22
32
25
620
35
0
28
40
30
1200
27
0
24
32
28
660
35
0
28
40
28
1280
28
0
23
33
25
830
21
0
22
31
23
680
26
0
23
32
27
640
21
0
28
39
28
1440
29
0

25
27
24
23
21
25
22
27
28
26
28
27
31
30
26
27
24
25
25
29
25
29
31
29
26
23
23
25
25
28
30
26
26
29
28
27
24
29
23
28
27
26
26
27
28
28
26

38
35
29
20
32
35
33
38
40
35
38
39
43
38
38
38
36
39
36
41
35
41
40
39
37
31
34
37
36
40
42
38
38
42
38
36
34
38
34
41
39
38
37
40
35
41
38

27
27
26
25
23
26
24
29
29
27
30
30
32
33
27
31
26
27
27
35
28
30
31
30
27
25
25
26
29
29
34
30
29
33
30
29
24
33
25
32
31
31
31
29
32
33
28

1150
850
760
620
660
985
690
1200
1370
1170
1200
1100
1480
1350
1160
1330
960
1080
1000
1490
880
1370
1325
1400
1240
660
780
950
850
1200
1440
1100
1250
1420
1400
1420
900
1160
820
1410
1300
1110
820
1150
880
1320
1080

32
32
24
19
41
33
17
26
20
25
30
32
33
34
23
30
22
35
26
34
18
23
18
20
29
18
25
14
39
32
35
23
18
28
19
36
29
33
39
29
33
30
30
28
35
36
36

0
0
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
1
1
0
1
0
0
0
0
0
0
0
1
1
0
1
0
0
0
1
0
1
1
0
1
0
1
1
0