In: Statistics and Probability
1) You conduct a stepwise regression according to the following procedure:
Step 1: HS_SCI only
Step 2: HS_SCI and HS_ENG
Step 3: HS_SCI, HS_ENG and HS_MATH
Step 4: HS_SCI, HS_ENG, HS_MATH and PARENT EDUC
Step 5: HS_SCI, HS_ENG and HS_MATH, PARENT EDUC AND GENDER
Step 6: HS_SCI, HS_ENG and HS_MATH, PARENT EDUC, GENDER and ATAR
Present the regression output for each of the six steps.
Choice of reference category: It is recommended that you choose U (undergraduate education) as the reference category for the categorical variable: PARENT EDUC.
2) For eachof the independent variables contained in the regression model in Step 5, fullyinterpret the regression (slope) coefficients and comment on their statistical significance.
In discussing statistical significance of a regression coefficient, you have to justify your choice of a one or two tail test.
3) In stepwise regression Step 6you noticed that the regression coefficient of ATAR is negative (!). Does this result surprise you, given the correlation of ATAR and GPA? Why/Why not? Does the inclusion of ATAR improve overall model fit? Discuss fully.
DATA SAET:
Student ID | GPA | HS_SCI | HS_ENG | HS_MATH | ATAR | PARENT EDUC | GENDER |
1 | 6.75 | 10 | 10 | 10 | 91.6 | P | M |
2 | 3.78 | 6 | 6 | 6 | 55.3 | S | M |
3 | 4.11 | 6 | 8 | 8 | 74.95 | U | M |
4 | 3.64 | 10 | 7 | 9 | 84.05 | U | M |
5 | 5.91 | 9 | 8 | 8 | 77.55 | U | M |
6 | 5.75 | 8 | 8 | 10 | 78.3 | U | M |
7 | 5.35 | 10 | 10 | 8 | 89.75 | S | M |
8 | 1.99 | 10 | 7 | 10 | 85.45 | S | M |
9 | 4.81 | 10 | 10 | 10 | 90.25 | P | M |
10 | 4.09 | 7 | 6 | 7 | 64.8 | U | M |
11 | 5.39 | 10 | 6 | 9 | 84.55 | U | M |
12 | 5.84 | 9 | 7 | 5 | 67.95 | U | M |
13 | 1.59 | 5 | 7 | 6 | 61.95 | S | M |
14 | 2.50 | 9 | 9 | 10 | 89.85 | U | M |
15 | 4.09 | 9 | 7 | 8 | 74.05 | S | M |
16 | 6.52 | 10 | 9 | 10 | 96.75 | U | M |
17 | 6.65 | 10 | 9 | 10 | 93.9 | U | M |
18 | 7.00 | 9 | 8 | 9 | 86.55 | U | M |
19 | 3.50 | 6 | 5 | 9 | 66.95 | U | M |
20 | 5.25 | 10 | 9 | 10 | 96 | P | M |
21 | 4.06 | 7 | 8 | 9 | 74.05 | U | M |
22 | 4.58 | 8 | 7 | 9 | 79.25 | P | M |
23 | 5.37 | 4 | 7 | 7 | 58.3 | S | M |
24 | 5.18 | 7 | 6 | 9 | 66.3 | U | M |
25 | 6.56 | 9 | 9 | 10 | 92.35 | U | M |
26 | 5.46 | 10 | 7 | 10 | 89.4 | S | M |
27 | 3.93 | 7 | 4 | 9 | 68.3 | S | M |
28 | 5.30 | 8 | 7 | 8 | 74.95 | S | M |
29 | 1.35 | 6 | 6 | 7 | 57.65 | S | M |
30 | 5.60 | 5 | 7 | 9 | 68.6 | P | M |
31 | 2.45 | 8 | 8 | 6 | 68.35 | S | M |
32 | 4.60 | 10 | 6 | 10 | 81.95 | S | M |
33 | 3.36 | 10 | 8 | 9 | 86 | S | M |
34 | 5.12 | 10 | 10 | 10 | 97.45 | U | M |
35 | 6.54 | 10 | 9 | 9 | 84.85 | P | M |
36 | 4.95 | 9 | 9 | 10 | 92.75 | U | M |
37 | 5.42 | 10 | 9 | 9 | 86.25 | U | M |
38 | 4.20 | 6 | 6 | 7 | 59.2 | S | M |
39 | 4.88 | 6 | 7 | 9 | 70.45 | S | M |
40 | 3.37 | 6 | 8 | 8 | 76.05 | S | M |
41 | 3.79 | 7 | 7 | 10 | 74.2 | U | M |
42 | 3.13 | 7 | 5 | 7 | 66.05 | S | M |
43 | 5.86 | 10 | 10 | 10 | 84.25 | U | M |
44 | 6.31 | 10 | 9 | 10 | 88.9 | P | M |
45 | 4.81 | 7 | 5 | 10 | 73.65 | U | M |
46 | 6.26 | 7 | 8 | 10 | 77.8 | P | M |
47 | 4.83 | 10 | 10 | 10 | 90.35 | P | M |
48 | 6.42 | 10 | 10 | 10 | 97.3 | U | M |
49 | 6.66 | 10 | 7 | 10 | 90.2 | U | M |
50 | 5.53 | 9 | 8 | 10 | 87 | S | M |
51 | 5.53 | 7 | 7 | 9 | 77.6 | P | M |
52 | 6.33 | 10 | 8 | 10 | 92 | U | M |
53 | 3.93 | 9 | 10 | 6 | 81.8 | S | M |
54 | 4.46 | 8 | 8 | 7 | 74 | U | M |
55 | 4.93 | 9 | 9 | 10 | 91.45 | U | M |
56 | 5.68 | 7 | 8 | 9 | 73.5 | U | M |
57 | 3.71 | 7 | 8 | 7 | 73.95 | S | M |
58 | 3.29 | 6 | 6 | 10 | 75.95 | S | M |
59 | 4.63 | 10 | 8 | 8 | 82 | S | M |
60 | 3.22 | 6 | 6 | 9 | 64 | S | M |
61 | 3.86 | 7 | 8 | 7 | 73.65 | S | M |
62 | 5.18 | 7 | 8 | 9 | 72.8 | P | M |
63 | 4.23 | 6 | 8 | 6 | 61.3 | S | M |
64 | 5.96 | 4 | 7 | 9 | 62.8 | P | M |
65 | 5.81 | 10 | 10 | 10 | 90.4 | P | M |
66 | 4.74 | 7 | 9 | 8 | 76.1 | U | M |
67 | 5.95 | 10 | 9 | 9 | 84.25 | U | M |
68 | 4.34 | 9 | 6 | 8 | 75.55 | S | M |
69 | 4.34 | 8 | 7 | 8 | 71.85 | U | M |
70 | 1.00 | 10 | 9 | 7 | 86.15 | P | M |
71 | 5.56 | 10 | 8 | 9 | 88.1 | P | M |
72 | 5.95 | 8 | 4 | 7 | 61.1 | S | M |
73 | 5.61 | 8 | 7 | 8 | 74.25 | S | M |
74 | 4.72 | 8 | 6 | 6 | 65.35 | S | M |
75 | 5.35 | 6 | 5 | 8 | 59.95 | U | M |
76 | 7.00 | 10 | 10 | 9 | 95.05 | U | M |
77 | 6.12 | 7 | 8 | 8 | 69.8 | S | M |
78 | 4.91 | 7 | 4 | 9 | 68.35 | U | M |
79 | 3.16 | 9 | 9 | 9 | 87.5 | P | M |
80 | 6.47 | 10 | 10 | 10 | 96.45 | U | M |
81 | 5.04 | 7 | 6 | 9 | 71.35 | S | M |
82 | 4.62 | 9 | 8 | 9 | 82.85 | U | M |
83 | 5.40 | 10 | 8 | 10 | 84.2 | U | M |
84 | 4.93 | 5 | 7 | 4 | 51.15 | S | M |
85 | 5.19 | 10 | 10 | 10 | 95.55 | U | M |
86 | 4.91 | 10 | 10 | 10 | 98.25 | U | M |
87 | 5.81 | 9 | 10 | 10 | 91.5 | U | M |
88 | 5.61 | 9 | 8 | 7 | 75.8 | S | M |
89 | 6.47 | 10 | 8 | 8 | 87.9 | S | M |
90 | 5.35 | 9 | 9 | 5 | 73.95 | S | M |
91 | 5.02 | 9 | 9 | 9 | 81.15 | S | M |
92 | 3.71 | 6 | 7 | 7 | 69.55 | P | M |
93 | 3.95 | 7 | 7 | 5 | 63.55 | U | M |
94 | 3.55 | 7 | 9 | 6 | 74.4 | U | M |
95 | 4.25 | 10 | 10 | 7 | 82.3 | U | M |
96 | 4.37 | 9 | 9 | 10 | 90.35 | S | M |
97 | 2.90 | 4 | 3 | 8 | 49.75 | U | M |
98 | 5.96 | 9 | 9 | 9 | 88.9 | U | M |
99 | 3.41 | 8 | 9 | 7 | 77.25 | S | M |
100 | 5.82 | 6 | 7 | 7 | 64.1 | U | M |
101 | 2.78 | 9 | 7 | 8 | 77.5 | S | M |
102 | 4.30 | 7 | 7 | 6 | 66.9 | U | M |
103 | 6.02 | 10 | 9 | 10 | 96.35 | S | M |
104 | 2.95 | 7 | 7 | 8 | 75.05 | S | M |
105 | 1.30 | 7 | 7 | 9 | 72.8 | U | M |
106 | 4.88 | 8 | 7 | 8 | 70.6 | P | M |
107 | 1.00 | 6 | 6 | 4 | 58.05 | S | M |
108 | 3.57 | 7 | 7 | 8 | 70.15 | S | M |
109 | 3.50 | 5 | 6 | 6 | 57 | S | M |
110 | 2.34 | 7 | 8 | 6 | 64.25 | U | M |
111 | 4.02 | 10 | 10 | 9 | 90.65 | P | M |
112 | 5.70 | 10 | 9 | 10 | 95.75 | P | M |
113 | 5.49 | 8 | 9 | 9 | 83.2 | U | M |
114 | 3.93 | 10 | 10 | 10 | 93.6 | U | M |
115 | 1.75 | 9 | 10 | 8 | 91 | U | M |
116 | 4.86 | 9 | 10 | 9 | 89.75 | S | M |
117 | 3.95 | 8 | 5 | 6 | 65.7 | S | M |
118 | 3.69 | 9 | 9 | 6 | 72.4 | S | M |
119 | 4.95 | 7 | 7 | 6 | 63.85 | S | M |
120 | 1.00 | 7 | 7 | 5 | 59.45 | S | M |
121 | 4.37 | 9 | 9 | 9 | 81.1 | U | M |
122 | 4.77 | 8 | 7 | 9 | 79.05 | S | M |
123 | 4.27 | 8 | 8 | 8 | 73.55 | U | M |
124 | 1.94 | 7 | 7 | 7 | 69.35 | U | M |
125 | 5.46 | 10 | 10 | 10 | 96.3 | U | M |
126 | 3.79 | 7 | 8 | 8 | 70.25 | U | M |
127 | 3.50 | 7 | 6 | 3 | 53.25 | S | M |
128 | 3.18 | 8 | 6 | 6 | 64.2 | S | M |
129 | 5.63 | 7 | 9 | 9 | 84.2 | U | M |
130 | 5.39 | 10 | 8 | 9 | 82.85 | S | M |
131 | 1.40 | 10 | 9 | 8 | 85 | S | M |
132 | 4.51 | 9 | 9 | 10 | 87.95 | U | M |
133 | 3.76 | 6 | 6 | 6 | 62.2 | S | M |
134 | 4.37 | 10 | 10 | 7 | 89.2 | U | M |
135 | 3.23 | 8 | 7 | 10 | 84.15 | U | M |
136 | 1.87 | 8 | 6 | 7 | 66.55 | S | M |
137 | 5.16 | 9 | 8 | 9 | 80.3 | U | M |
138 | 6.51 | 8 | 7 | 7 | 70.8 | U | M |
139 | 1.21 | 6 | 7 | 6 | 61.55 | S | M |
140 | 4.67 | 9 | 10 | 9 | 93.35 | U | M |
141 | 4.39 | 8 | 7 | 9 | 76.3 | U | M |
142 | 2.55 | 7 | 8 | 7 | 72.1 | S | M |
143 | 4.18 | 5 | 6 | 6 | 57.4 | S | M |
144 | 5.25 | 3 | 4 | 4 | 35.05 | S | M |
145 | 5.86 | 10 | 10 | 10 | 92.9 | P | M |
146 | 4.27 | 9 | 9 | 10 | 86.25 | S | F |
147 | 5.86 | 9 | 9 | 9 | 88.25 | U | F |
148 | 6.65 | 9 | 8 | 10 | 90.4 | U | F |
149 | 4.56 | 7 | 8 | 9 | 73.15 | P | F |
150 | 4.90 | 9 | 9 | 10 | 92.45 | P | F |
151 | 5.74 | 10 | 10 | 10 | 91 | P | F |
152 | 5.02 | 8 | 7 | 8 | 69.65 | U | F |
153 | 5.53 | 9 | 8 | 8 | 76.75 | U | F |
154 | 5.37 | 8 | 9 | 9 | 79.4 | U | F |
155 | 6.44 | 8 | 9 | 10 | 89.65 | U | F |
156 | 5.84 | 9 | 10 | 10 | 88.1 | U | F |
157 | 6.05 | 9 | 8 | 9 | 86.05 | S | F |
158 | 4.25 | 5 | 9 | 9 | 72.65 | U | F |
159 | 4.84 | 5 | 9 | 6 | 64.75 | P | F |
160 | 6.40 | 10 | 10 | 10 | 90.7 | U | F |
161 | 3.25 | 9 | 7 | 7 | 75.55 | S | F |
162 | 3.41 | 6 | 9 | 6 | 68.2 | S | F |
163 | 5.35 | 10 | 10 | 10 | 96.2 | U | F |
164 | 3.39 | 8 | 8 | 8 | 73.95 | S | F |
165 | 5.49 | 9 | 10 | 9 | 91.6 | U | F |
166 | 4.98 | 8 | 8 | 10 | 79.45 | U | F |
167 | 6.07 | 10 | 9 | 10 | 96.25 | U | F |
168 | 5.93 | 10 | 10 | 10 | 86.25 | S | F |
169 | 6.82 | 10 | 10 | 10 | 91.8 | U | F |
170 | 6.38 | 9 | 9 | 9 | 83.15 | U | F |
171 | 6.37 | 6 | 8 | 8 | 72.4 | S | F |
172 | 4.83 | 10 | 10 | 10 | 96.35 | S | F |
173 | 5.00 | 9 | 10 | 10 | 91.05 | U | F |
174 | 4.39 | 9 | 10 | 8 | 85.85 | U | F |
175 | 5.00 | 9 | 8 | 8 | 78.35 | U | F |
176 | 5.84 | 9 | 9 | 10 | 85.1 | U | F |
177 | 5.82 | 7 | 9 | 9 | 82.85 | U | F |
178 | 6.45 | 10 | 8 | 10 | 90.65 | U | F |
179 | 3.15 | 7 | 7 | 7 | 65.35 | U | F |
180 | 4.49 | 10 | 10 | 9 | 90.85 | U | F |
181 | 3.99 | 10 | 10 | 8 | 92.8 | U | F |
182 | 3.50 | 4 | 6 | 2 | 44.55 | S | F |
183 | 4.42 | 9 | 8 | 8 | 81 | S | F |
184 | 2.95 | 6 | 7 | 7 | 60.25 | U | F |
185 | 5.35 | 10 | 9 | 9 | 86.6 | U | F |
186 | 4.81 | 9 | 8 | 8 | 81.9 | U | F |
187 | 4.58 | 10 | 8 | 9 | 87.45 | U | F |
188 | 3.74 | 4 | 8 | 5 | 54.85 | U | F |
189 | 3.37 | 8 | 8 | 10 | 87.35 | S | F |
190 | 5.00 | 4 | 8 | 9 | 70.35 | S | F |
191 | 4.14 | 7 | 9 | 8 | 78.35 | U | F |
192 | 2.18 | 8 | 6 | 7 | 66.75 | U | F |
193 | 5.56 | 10 | 10 | 10 | 95.35 | P | F |
194 | 5.77 | 10 | 9 | 10 | 88.9 | S | F |
195 | 4.00 | 6 | 8 | 7 | 72.15 | S | F |
196 | 4.74 | 7 | 10 | 9 | 84.05 | U | F |
197 | 4.53 | 10 | 10 | 10 | 90.45 | U | F |
198 | 5.93 | 9 | 10 | 9 | 85.35 | P | F |
199 | 4.28 | 7 | 8 | 7 | 73.3 | S | F |
200 | 4.53 | 4 | 7 | 5 | 51.5 | S | F |
201 | 4.51 | 10 | 9 | 10 | 89.35 | P | F |
202 | 4.70 | 6 | 9 | 8 | 70.2 | U | F |
203 | 4.42 | 6 | 9 | 7 | 72.1 | S | F |
204 | 5.25 | 8 | 9 | 10 | 86.2 | U | F |
205 | 3.62 | 7 | 6 | 9 | 66.95 | S | F |
206 | 3.23 | 8 | 10 | 10 | 92.75 | U | F |
207 | 5.84 | 9 | 10 | 10 | 95.2 | U | F |
208 | 4.76 | 5 | 7 | 6 | 61.55 | P | F |
209 | 7.00 | 10 | 10 | 10 | 94.8 | U | F |
210 | 5.95 | 9 | 9 | 6 | 75.55 | P | F |
211 | 5.12 | 9 | 10 | 9 | 91.05 | P | F |
212 | 3.83 | 5 | 6 | 6 | 57.5 | S | F |
213 | 5.81 | 9 | 10 | 10 | 87.1 | S | F |
214 | 5.96 | 6 | 8 | 8 | 69.85 | S | F |
215 | 3.15 | 7 | 9 | 8 | 76.15 | U | F |
216 | 2.66 | 9 | 10 | 9 | 86.1 | U | F |
217 | 4.16 | 9 | 10 | 9 | 87.75 | P | F |
218 | 3.65 | 7 | 8 | 9 | 74.35 | S | F |
219 | 5.65 | 10 | 10 | 10 | 98.75 | S | F |
220 | 2.31 | 8 | 9 | 9 | 81.4 | S | F |
221 | 4.06 | 6 | 7 | 6 | 58.8 | S | F |
222 | 1.48 | 7 | 9 | 7 | 72.35 | S | F |
223 | 2.80 | 7 | 7 | 4 | 56.95 | S | F |
224 | 3.99 | 8 | 9 | 9 | 79.45 | U |
F |
Spss used.
PARENT EDUC coded as edu1 with 0 for U , 1 for S and P for 2
Gender is coded as gender1 with M=1 and F=0.
1) You conduct a stepwise regression according to the following procedure:
Step 1: HS_SCI only
Step 2: HS_SCI and HS_ENG
Step 3: HS_SCI, HS_ENG and HS_MATH
Step 4: HS_SCI, HS_ENG, HS_MATH and PARENT EDUC
Step 5: HS_SCI, HS_ENG and HS_MATH, PARENT EDUC AND GENDER
Step 6: HS_SCI, HS_ENG and HS_MATH, PARENT EDUC, GENDER and ATAR
Present the regression output for each of the six steps.
Choice of reference category: It is recommended that you choose U (undergraduate education) as the reference category for the categorical variable: PARENT EDUC.
Spss syntax.
REGRESSION
/MISSING LISTWISE
/STATISTICS COEFF OUTS R ANOVA
/CRITERIA=PIN(.05) POUT(.10)
/NOORIGIN
/DEPENDENT GPA
/METHOD=ENTER HS_SCI
/METHOD=ENTER HS_ENG
/METHOD=ENTER HS_MATH
/METHOD=ENTER edu1
/METHOD=ENTER gender1
/METHOD=ENTER ATAR.
Model Summary |
||||
Model |
R |
R Square |
Adjusted R Square |
Std. Error of the Estimate |
1 |
.344a |
.119 |
.115 |
1.25303 |
2 |
.367b |
.135 |
.127 |
1.24408 |
3 |
.464c |
.215 |
.205 |
1.18761 |
4 |
.464d |
.215 |
.201 |
1.19022 |
5 |
.465e |
.216 |
.198 |
1.19232 |
6 |
.465f |
.216 |
.195 |
1.19491 |
a. Predictors: (Constant), HS_SCI |
||||
b. Predictors: (Constant), HS_SCI, HS_ENG |
||||
c. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH |
||||
d. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH, edu1 |
||||
e. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH, edu1, gender1 |
||||
f. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH, edu1, gender1, ATAR |
ANOVAa |
||||||
Model |
Sum of Squares |
df |
Mean Square |
F |
Sig. |
|
1 |
Regression |
46.870 |
1 |
46.870 |
29.852 |
.000b |
Residual |
348.557 |
222 |
1.570 |
|||
Total |
395.427 |
223 |
||||
2 |
Regression |
53.380 |
2 |
26.690 |
17.245 |
.000c |
Residual |
342.047 |
221 |
1.548 |
|||
Total |
395.427 |
223 |
||||
3 |
Regression |
85.137 |
3 |
28.379 |
20.121 |
.000d |
Residual |
310.290 |
220 |
1.410 |
|||
Total |
395.427 |
223 |
||||
4 |
Regression |
85.185 |
4 |
21.296 |
15.033 |
.000e |
Residual |
310.242 |
219 |
1.417 |
|||
Total |
395.427 |
223 |
||||
5 |
Regression |
85.512 |
5 |
17.102 |
12.030 |
.000f |
Residual |
309.915 |
218 |
1.422 |
|||
Total |
395.427 |
223 |
||||
6 |
Regression |
85.594 |
6 |
14.266 |
9.991 |
.000g |
Residual |
309.833 |
217 |
1.428 |
|||
Total |
395.427 |
223 |
||||
a. Dependent Variable: GPA |
||||||
b. Predictors: (Constant), HS_SCI |
||||||
c. Predictors: (Constant), HS_SCI, HS_ENG |
||||||
d. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH |
||||||
e. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH, edu1 |
||||||
f. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH, edu1, gender1 |
||||||
g. Predictors: (Constant), HS_SCI, HS_ENG, HS_MATH, edu1, gender1, ATAR |
Coefficientsa |
||||||
Model |
Unstandardized Coefficients |
Standardized Coefficients |
t |
Sig. |
||
B |
Std. Error |
Beta |
||||
1 |
(Constant) |
2.422 |
.408 |
5.935 |
.000 |
|
HS_SCI |
.270 |
.049 |
.344 |
5.464 |
.000 |
|
2 |
(Constant) |
1.875 |
.485 |
3.865 |
.000 |
|
HS_SCI |
.198 |
.060 |
.253 |
3.297 |
.001 |
|
HS_ENG |
.139 |
.068 |
.157 |
2.051 |
.041 |
|
3 |
(Constant) |
.988 |
.499 |
1.979 |
.049 |
|
HS_SCI |
.067 |
.064 |
.085 |
1.049 |
.295 |
|
HS_ENG |
.086 |
.066 |
.097 |
1.310 |
.192 |
|
HS_MATH |
.286 |
.060 |
.352 |
4.745 |
.000 |
|
4 |
(Constant) |
1.011 |
.516 |
1.960 |
.051 |
|
HS_SCI |
.067 |
.064 |
.085 |
1.043 |
.298 |
|
HS_ENG |
.086 |
.066 |
.097 |
1.308 |
.192 |
|
HS_MATH |
.285 |
.061 |
.351 |
4.702 |
.000 |
|
edu1 |
-.021 |
.113 |
-.011 |
-.184 |
.854 |
|
5 |
(Constant) |
1.116 |
.561 |
1.989 |
.048 |
|
HS_SCI |
.074 |
.066 |
.095 |
1.127 |
.261 |
|
HS_ENG |
.073 |
.071 |
.083 |
1.033 |
.303 |
|
HS_MATH |
.284 |
.061 |
.349 |
4.670 |
.000 |
|
edu1 |
-.018 |
.113 |
-.009 |
-.157 |
.875 |
|
gender1 |
-.087 |
.181 |
-.031 |
-.480 |
.632 |
|
6 |
(Constant) |
1.153 |
.583 |
1.978 |
.049 |
|
HS_SCI |
.094 |
.105 |
.120 |
.894 |
.372 |
|
HS_ENG |
.092 |
.104 |
.104 |
.880 |
.380 |
|
HS_MATH |
.303 |
.101 |
.373 |
2.992 |
.003 |
|
edu1 |
-.019 |
.113 |
-.010 |
-.169 |
.866 |
|
gender1 |
-.084 |
.182 |
-.030 |
-.460 |
.646 |
|
ATAR |
-.006 |
.027 |
-.060 |
-.240 |
.811 |
|
a. Dependent Variable: GPA |
2) For eachof the independent variables contained in the regression model in Step 5, fullyinterpret the regression (slope) coefficients and comment on their statistical significance.
All two tailed test is used.
To test the significance of HS_SCI, calculated t=1.127, P=0.261 which is > 0.05 level. This is not significant.
To test the significance of HS_ENG, calculated t=1.033, P=0.303 which is > 0.05 level. This is not significant.
To test the significance of HS_MATH, calculated t=4.670, P=0.000 which is < 0.05 level. This is significant.
To test the significance of PARENT EDUC, calculated t=-0.157, P=0.875 which is > 0.05 level. This is not significant.
To test the significance of GENDER, calculated t=-0.480, P=0.632 which is > 0.05 level. This is not significant
5 |
(Constant) |
1.116 |
.561 |
1.989 |
.048 |
|
HS_SCI |
.074 |
.066 |
.095 |
1.127 |
.261 |
|
HS_ENG |
.073 |
.071 |
.083 |
1.033 |
.303 |
|
HS_MATH |
.284 |
.061 |
.349 |
4.670 |
.000 |
|
edu1 |
-.018 |
.113 |
-.009 |
-.157 |
.875 |
|
gender1 |
-.087 |
.181 |
-.031 |
-.480 |
.632 |
In discussing statistical significance of a regression coefficient, you have to justify your choice of a one or two tail test.
3) In stepwise regression Step 6you noticed that the regression coefficient of ATAR is negative (!). Does this result surprise you, given the correlation of ATAR and GPA? Why/Why not? Does the inclusion of ATAR improve overall model fit? Discuss fully.
regression coefficient of ATAR is -0.006 which is negative.
Correlations |
|||
GPA |
ATAR |
||
GPA |
Pearson Correlation |
1 |
.424** |
Sig. (2-tailed) |
.000 |
||
N |
224 |
224 |
|
ATAR |
Pearson Correlation |
.424** |
1 |
Sig. (2-tailed) |
.000 |
||
N |
224 |
224 |
|
**. Correlation is significant at the 0.01 level (2-tailed). |
Correlation of ATAR and GPA is 0.424 which is positive.
But regression coefficient of ATAR is -0.006 which is negative shows that some other independent variable is in the model is highly correlated with ATAR. After including ATAR, the R square value remains same as 0.216. There fore inclusion of ATAR does not improve overall model fit.